mia_material for realistic leaves

[tharrell]

Translucency is going to get you half of the way there, but you're likely going to want to do some subsurface scattering and add an extra layer or two of specular (a wide rough one, and a tight one, much like skin).

The preferred workflow for skin & other organics these days is to pipe the output of a subsurface shader as additional color atop an mia_material. You can paint veining in your leaves in the subsurface layer, and turn off the specular and diffuse in your sub layer as well (unless they look good, then keep 'em in :)

Hope this helps,

--T

[royterr]

Translucency is going to get you half of the way there, but you're likely going to want to do some subsurface scattering and add an extra layer or two of specular (a wide rough one, and a tight one, much like skin).

The preferred workflow for skin & other organics these days is to pipe the output of a subsurface shader as additional color atop an mia_material. You can paint veining in your leaves in the subsurface layer, and turn off the specular and diffuse in your sub layer as well (unless they look good, then keep 'em in :)

Hope this helps,

--T

if i plug a sss shader to the aditional color of the mia_material then it wouldn't be physically correct because the mia_material is based on this formula : diffue+reflection+refraction=1. Now if you add an aditional color, it will be added to the overall value and it would be bigger than 1.
Besides, what really happens in the sahder when you plug an sss to the aditional color slot?

[tharrell]

if i plug a sss shader to the aditional color of the mia_material then it wouldn't be physically correct because the mia_material is based on this formula : diffue+reflection+refraction=1. Now if you add an aditional color, it will be added to the overall value and it would be bigger than 1.

That's absolutely correct. The color of your diffuse + specular reflection can't exceed 1 for it to be energy conserving. You generally dial down your diffuse level to compensate for the piped through SSS, but it won't be "physically accurate".

That said, there's a distinction to be made between "physical accuracy" and "it looks awesome". Most folks using fast_skin are using the diffuse in mia_mat these days and using the workflow that I just described.

Translucence is cheated SSS + transparency by the way, very much not physically accurate.

Besides, what really happens in the sahder when you plug an sss to the aditional color slot?

In a nutshell, this:

http://forums.cgsociety.org/showthread.php?f=121&t=629792

(that's the "skinplus" workflow in 3DSmax -- SSS into additional color on an mia)

Granted it's skin. But look nice and closely at the greens and how they fade into shadow...

--T

[royterr]

That's absolutely correct. The color of your diffuse + specular reflection can't exceed 1 for it to be energy conserving. You generally dial down your diffuse level to compensate for the piped through SSS, but it won't be "physically accurate".

That said, there's a distinction to be made between "physical accuracy" and "it looks awesome". Most folks using fast_skin are using the diffuse in mia_mat these days and using the workflow that I just described.

Translucence is cheated SSS + transparency by the way, very much not physically accurate.



In a nutshell, this:

http://forums.cgsociety.org/showthread.php?f=121&t=629792

(that's the "skinplus" workflow in 3DSmax -- SSS into additional color on an mia)

Granted it's skin. But look nice and closely at the greens and how they fade into shadow...

--T

so you plug your sss shader to your mia_material aditional color slot, why not diretcly the diffuse?

if i get it right: - reflections/specular and part of the diffuse are driven by the mia_material
- part of the diffuse are also driven by he mia_material
- what drives the transparency then?

regarding the hulk thread, wich page talk about the shading network details , didn't find it.

[tharrell]

Generally, instead of using the diffuse component on (say) a fast_skin, you use the diffuse on the mia_material at .3-.5ish contribution instead. You're turning off the diffuse on the SSS mat entirely so that stuff doesn't get blown out, and it maintains some semblance of physical accuracy (ie not reflecting more light than hits it).

Here's a post by Zap (who programmed fast skin and the arch mats) talking about the workflow in 3ds Max... pretty much the same in Maya, except the connections are easier and you don't need a specialized .mi to do it.... maya details are down in the commments section.

Just apply the fast_skin to an object first, so that the lightmaps etc etc are created, and paste them from the fast skin shading group to the mia_mat shading group.

http://mentalraytips.blogspot.com/2008/04/beauty-isnt-only-skin-deep-combining.html

And it looks pretty darned awesome. Used this workflow for an aloe plant on a gig not too long ago and it looked phenomenal.... can't find examples at the moment, but I'll post em if I find them.

--T

[tharrell]

Also worth mentioning that you use the diffuse to keep from having to check "use indirect illumination" on your fast skin....

There's been a bug in Maya 2009 and 2010 that SSS lightmaps take an eternity to calculate if final gather is turned on. Of course AD talked it up as a feature... something like "due to more accurate calculations, SSS maps with final gather now take a billion times longer to generate".

Scenes rendering 10x as slow from Maya 2008 to 2009 qualify as a bug to me.

But I digress...

Anyhow, I generally cheat my mia_diffuse a little higher than I should to compensate for the lack of FG contribution in my subsurface, because render times including indirect in my SSS are intolerable.

--T

[fabergambis]

I usually use a mia_material_x with at least 0.2/0.25 transparency, a 0.95 translucency weight with a solid clear green color instead of the same texture I use for diffuse, otherwise the effect I get is too dark, or you should use a clearer version of the diffuse texture.
Never tested any of the SSS shaders for leaves but in most cases I think the mia should be faster and easier: it depends on your needs.

[royterr]

I usually use a mia_material_x with at least 0.2/0.25 transparency, a 0.95 translucency weight with a solid clear green color instead of the same texture I use for diffuse, otherwise the effect I get is too dark, or you should use a clearer version of the diffuse texture.
Never tested any of the SSS shaders for leaves but in most cases I think the mia should be faster and easier: it depends on your needs.

for mid range/ background leaves, i would definitivly use the mia_material with similar values.

tharrell (http://forums.cgsociety.org/member.php?u=103181), thanks alot for the info, your method is specially useful for hero objects.
- if i got it right you copy and paste the lightmaps of a misss_fast_skin_maya shader to the mia_material SG.
- drag the sss shader to the additional color of the mia_material
- apply the mia_material to the object.
-turn off diifuse color and weight of the sss shader (what about the overall color slot?)
- play around with the "Subsurface Scaterring layer" values

- But mastezap mentioned that you also should turn off "unscattered diffuse" in the sss sahder. I can't find that section

-did the AD fixed the bug of lightmaps rendering superslow with FG in Maya 2010?

[tharrell]

Yep, you've got it right.

The diffuse that you turn off is the ambient color (leave black) overall color (leave white) and the diffuse color (leave blueish, but turn the weight to 0). It's the block at the top of the node.

The overall color is a multiplier on the entire network, so if you like the look but it's too bright, you can scale it down with that.

Yeah, definitely not suggesting that you put SSS on a billion background objects that you can cheat, but for hero stuff up close to camera it looks really nice.

And no, the bug isn't fixed in 2010... it's a feature now!

--T

[InfernalDarkness]

...but if it's a personal (no NDA) project, would you mind sharing your results Roy? As you make progress, I mean. No rush. I'm working on a personal "landscape" project in a similar vein as our hero Alessandro, and having a nightmare of a time with my leaves...

But I have been significantly impressed with MR under Win7 x64 / Maya 2009 x64. Pushing many millions of polys more (at rendertime) than I ever was able to do a year ago. I hope you're experiencing the same luxuries, because when I originally saw Alessandro's work, it truly seemed impossible to do with Maya. Now, it's still impossible to match, but hopefully one can get close to that level of detail and realism!

Anyway, this thread rocks and thanks to all for posting helpful ideas and techniques.

[royterr]

...but if it's a personal (no NDA) project, would you mind sharing your results Roy? As you make progress, I mean. No rush. I'm working on a personal "landscape" project in a similar vein as our hero Alessandro, and having a nightmare of a time with my leaves...

But I have been significantly impressed with MR under Win7 x64 / Maya 2009 x64. Pushing many millions of polys more (at rendertime) than I ever was able to do a year ago. I hope you're experiencing the same luxuries, because when I originally saw Alessandro's work, it truly seemed impossible to do with Maya. Now, it's still impossible to match, but hopefully one can get close to that level of detail and realism!

Anyway, this thread rocks and thanks to all for posting helpful ideas and techniques.

Of course!
i did some tests with leaves some time ago and it's generally easy to get descent results with good texturing.
My main focus right now is to model/shade grass like Alessandro's impressing grass, it's much harder than leaves.
Anyways, i will post renders/files regarding the progress for leaves and grass, so that we could join forces.

btw how many triangles are you able to handle in your viewport shaded, textured?

[InfernalDarkness]

Well when you say "handle" it could mean "and still tumble / zoom in this lifetime", or it could just mean total display handling. So far I've hit no limit on how many polys it will display, and my scene may have 10 million or so. But I have to use a great many display layers (PFX_plants_far, PFX_plants_near_right, Poly_trees_far, and on like that) to make the scene functional for zooming and stuff. I imagine the poly-limit / frame-rate factor is similar to gaming performance on this card, which isn't horrible, but if I were pushing the same 10 million polys (faces) in Unreal 3 or Protoype for example it would probably bog down just as much.

But my homestation only has a Geforce 7950GT in it, with 512MB of RAM. Not a "recent" GPU by any means. I'll post a screenshot at some point but I don't intend to hijack your thread, my friend! It's good to know there are others working on similar things, though. Thanks for sharing and for all the tips.

[eem]

royterr, this has been a subject on my mind for a long time and something I play around with quite a bit. I would like to know the ideal way to set up leaf and grass materials as well.

I asked allesandro over on evermotion about his mia_material settings for leaves but he never responded. IIRC correctly in a post he did mention he used all mia_material, and I don't remember him mentioning misss. So I assume his plants have no misss shader in the mix. Of course, I could be completely wrong, I have no idea. But from looking at his renders, they do not look like they have misss shaders on them to me. I think it might be very proper adjustment of mia_material settings and colors, and then very well done color correction.

The thin-walled translucency function on the mia_material was designed for exactly this purpose and I do think it offers all that is required for grass blades and thin walled leaves. I mean, the misss shaders don't even calculate properly on thin-walled surfaces do they? I thought they were intended for sealed meshes with volume.

I'll run some tests myself and post them.

[royterr]

The thin-walled translucency function on the mia_material was designed for exactly this purpose and I do think it offers all that is required for grass blades and thin walled leaves. I mean, the misss shaders don't even calculate properly on thin-walled surfaces do they? I thought they were intended for sealed meshes with volume.


my intuition also tells me it's the mia_material that has been used in the scene.
it's going te be a tough one but nothing is inpossible.

The first thing i noticed is that the ground beneath the grass is textured with some leaves/soil texture and helps really alot in giving the impression of dense grass covering all the surface.

As for the geometry, i think he started with a PF grass perset and tweaked it alot because i have tried them all and nothing ressembles his grass.

i will post mt tests soon.

[eem]

One thing to note. Reflection, refracton and shadow raytracing depth have absolutely no effect whatsoever on the nature of how mia_material translucency propagates lighting through the leaves. You can leave all of them at 1 with no change in lighting.

Now, to be physically correct you want translucency weight at 1, since no leaf or grassblade is semi-transparent, they are fully translucent. So for all purposes of leaves and grassblades I set tranclucency weight to 1 and control the level of translucency purely with the transparency slider.

Transparency 1.0 (the darkness comes from me having the FG filter set to 2)
http://omploader.org/vMmEyYQ/transparency10.jpg

Transparency .8
http://omploader.org/vMmEyYg/transparency8.jpg

Transparency .6
http://omploader.org/vMmEyYw/transparency6.jpg

Transparency .4
http://omploader.org/vMmEyZA/transparency4.jpg

Transparency .2
http://omploader.org/vMmEyZQ/transparency2.jpg

Transparency 0
http://omploader.org/vMmEyag/transparency0.jpg


Now one thing about that series of images above is, the translucency color is brighter than the leaf color. I think that in some ways that makes it look more realistic because looking behind the leaves in the sun they appear brighter, but is that physically correct?

Here is a series of images where the only thing I'm adjusting is the brightness of the translucency color, which is a slightly yellow solid color. Transparency is set to .4 in all images.

Translucency Color 1
http://omploader.org/vMmEyaw/transclucencycolor10.jpg

TransclucenyColor .6
http://omploader.org/vMmEybA/transclucencycolor6.jpg

TranslucencyColor .3
http://omploader.org/vMmEybQ/transclucencycolor3.jpg

TranslucencyColor .1
http://omploader.org/vMmEybg/transclucencycolor1.jpg

So I think thin-walled translucency by itself is very capable of propagating a SSS effect through leaves by itself. The misss shaders I do not think are necessary. Just properly adjusted mia_material.

I think physically accurate would be with the diffuse color and translucency color about the same level of brightness. Then make the translucency color slightly tinted yellow, and maybe increased .1 brightness just for a little more behind the leaf shine.

[eem]

I think physically accurate would be with the diffuse color and translucency color about the same level of brightness. Then make the translucency color slightly tinted yellow, and maybe increased .1 brightness just for a little more behind the leaf shine.

and heres some renders with those settings

http://omploader.org/vMmEydQ/properset.jpg
http://omploader.org/vMmEydg/properset2.jpg
http://omploader.org/vMmEydw/properset3.jpg





and some allesandro style-esque color correcting

http://omploader.org/vMmEyeQ/CC.jpg

only not as good

here is the scene file if anyone wants to run some more tests
http://www.4shared.com/file/130083720/58ad2398/treeTest.html

[Mrguy]

for mid range/ background leaves, i would definitivly use the mia_material with similar values.

tharrell (http://forums.cgsociety.org/member.php?u=103181), thanks alot for the info, your method is specially useful for hero objects.
- if i got it right you copy and paste the lightmaps of a misss_fast_skin_maya shader to the mia_material SG.
- drag the sss shader to the additional color of the mia_material
- apply the mia_material to the object.
-turn off diifuse color and weight of the sss shader (what about the overall color slot?)
- play around with the "Subsurface Scaterring layer" values

- But mastezap mentioned that you also should turn off "unscattered diffuse" in the sss sahder. I can't find that section

-did the AD fixed the bug of lightmaps rendering superslow with FG in Maya 2010?

Whats the "additional color of the mia_material"? In SG; Custom shaders>material shader? or ? Confused on that part.

And could the light maps also be connected to the light map shader attribute instead of being copied and then connected?

[royterr]

Whats the "additional color of the mia_material"? In SG; Custom shaders>material shader? or ? Confused on that part.

And could the light maps also be connected to the light map shader attribute instead of being copied and then connected?

the aditional color is simply a slot in the advanced section of the mia_material.

i dont know how lightmaps work and if 2 materials can share the same light map.

[Mrguy]

I must be blind... is it a feature in 2010 only? I'm in 2009.

I'm checking out the shader network rygoody put up and he has oakLeaf.tif hooked into the cutout opacity? Not same thing?

[InfernalDarkness]

I'm checking out the shader network rygoody put up and he has oakLeaf.tif hooked into the cutout opacity? Not same thing?

Cutout opacity is where you put your alpha channel for cutout, as opposed to directly into the Transparency section on a standard Maya Blinn or Phong shader. Most of the time you'll need to check "Alpha is Luminance" on your file node too.

"Additional Color" is directly below Cutout Opacity in Maya 2009's mia_material_x. I haven't been using Additional Color on mine yet though... That said, I'm not getting results as sweet as Roy's in my leaves just yet. Close, but not as close as I'd like... Playing with translucency and transparency seems to be getting me close, but my scene's got seven different trees so far and tweaking them one by one is becoming tedious. Might have to create a break-out scene and then copy the material settings back in, for the sake of speeding up test-renders.

I'm not using SSS in mine (yet!) and hope not to, but if that's what it takes... The scene's already becoming almost too bulky, even under x64, so even more calc and render time might not work for me in the long run. Or, of course, a scene tear-down and reconstruction might help. I have a tendency to get sloppy with nodes on large projects.

[Mrguy]

Thats odd... I just got home and that section wasn't sowing up on my work computer for soe reason but shows up at home.

Ok very cool I'll work more on it tonight. I was actually going to use the setup for a face that I modeled.. sill far off but wanted to experiment a bit. I'm familiar with SSS Mix20 and blinn network but not mia and SSS so it intrigued me.

[royterr]

Cutout opacity is where you put your alpha channel for cutout, as opposed to directly into the Transparency section on a standard Maya Blinn or Phong shader. Most of the time you'll need to check "Alpha is Luminance" on your file node too.

"Additional Color" is directly below Cutout Opacity in Maya 2009's mia_material_x. I haven't been using Additional Color on mine yet though... That said, I'm not getting results as sweet as Roy's in my leaves just yet. Close, but not as close as I'd like... Playing with translucency and transparency seems to be getting me close, but my scene's got seven different trees so far and tweaking them one by one is becoming tedious. Might have to create a break-out scene and then copy the material settings back in, for the sake of speeding up test-renders.

I'm not using SSS in mine (yet!) and hope not to, but if that's what it takes... The scene's already becoming almost too bulky, even under x64, so even more calc and render time might not work for me in the long run. Or, of course, a scene tear-down and reconstruction might help. I have a tendency to get sloppy with nodes on large projects.

No need for an SSS shader because we are dealing with an open surface not a solid object.

I find the PF perset a good starting point, but you have to play around with twigs/branches/leafs settings alot to mimic real world trees.

Transulcency value should always be set to 1

For Translucency color:
-i think that using a flat color gives unrealistic results (check the back of the leaves, you will see an unatural flat color)
-Using a lighter version of your diffuse texture gives a very weak translucency result
-The Third opyion is to use a texture of the other side of the leaf wich is a solution bteween the last 2.
Frankly I don't know wich of these 3 options Masterzap wanted us to use.

For trasparency value:
-Everyone is using a value between 0 and 0.4. But when using a 0.8 value the leaves at the edges of the tree give a strong SSS feel but the areas in the shade look a bit "flat" due to this high translucency value (driven by the 0.8 transparency value).

That's what i found for now. I guess the big mystery lies in the last 2 points.

[YourDaftPunk]

For trasparency value:
-Everyone is using a value between 0 and 0.4. But when using a 0.8 value the leaves at the edges of the tree give a strong SSS feel but the areas in the shade look a bit "flat" due to this high translucency value (driven by the 0.8 transparency value).

If that's the case, you could use ambient occlusion as the value for transparency. The interior leaves would be dark in the AO pass so they would be between 0-0.4. The outer leaves would be occluded very little so they would be close to 1 in value. You chould then remap or clamp values so that no leaf's transparency goes above 0.8 or below 0.2.

..this may be overkill though.

[royterr]

Ok as promised here are my results:

http://sor.typepad.com/.a/6a00d8350600cb53ef0120a565a93e970b-pi
The most intresting result is the last one because it combines reflection on top of the leaves just like Alessandro's renders.
It's not perfect but close.
One of the key tricks is to have leaves facing the sky (more precsely the sun) in Paint Effects wich is quiet hard to achieve. i will post more details later:

[InfernalDarkness]

How did you achieve the topside and bottomside transparency numbers being different values? I'm no shader genius to be honest, and don't use a gamma-correct node workflow, so I'm having a hell of a time following your shader network.

The results are great to see though... I haven't learned or made this much progress in Maya in years, and you've been a great help. I find myself actually playing with Maya at home again, instead of loathing it after a long hard day's work and never opening it at home.

[AlexTNT]

how's my try ?

http://img258.imageshack.us/img258/9463/treetest03.jpg

1080p version here (http://img508.imageshack.us/img508/764/tree.png)

[Mrguy]

Hey InfernalDarkness I believe it's the condition node.

http://greensoda.squarespace.com/blog/2009/6/25/create-a-double-sided-shader-in-maya.html

And gamma nodes are just for on the spot adjusting right? Fix it in Maya rather then bring it back into PS?

[royterr]

Mrguy, you are right, i am using the gamma correct node because i am using a 2.2 gamma value in my mia_exposure_simple.So you have to correct everything, even color swatches ( i am not sure wether you have to gamma correct the "Ambient Shadow color" in the AO section)

As for the condition node, its very simple: you have a sampler info node that's inputing information about the normals and it's plugged to the first term of the condition node. and the condition node sees if the condition is availables ( so normal fliped) so if "color if true" has a white value (0 0 0) and "color if false" a 0.35 gray value.

I will post some more renders with better trees soon.

[tostao_wayne]

Mrguy, you are right, i am using the gamma correct node because i am using a 2.2 gamma value in my mia_exposure_simple.So you have to correct everything, even color swatches ( i am not sure wether you have to gamma correct the "Ambient Shadow color" in the AO section)

As for the condition node, its very simple: you have a sampler info node that's inputing information about the normals and it's plugged to the first term of the condition node. and the condition node sees if the condition is availables ( so normal fliped) so if "color if true" has a white value (0 0 0) and "color if false" a 0.35 gray value.

I will post some more renders with better trees soon.

royterr, in my opinion is a better way to use a Mib_twosided sample compositing instead a sampler_info.

by this way you can handle two independients mia_material, one for each side, you must think that for example the bump for one side must to be the oposite for the other side...

[tostao_wayne]

i'm agree with royter and rygoody,
.-the translucency value must to be always at 1
.-the translucency color must to be an image
.-the transparency color must to be white
.-you must to play with the transparency value to get the final result.

after that, i've notice that with backlight the leaf color intensity is almost the same as it has with front light, case by case and specie by specie, is not the same a maple than an olm oak, in the second case, the translucency is near to 0.

to mimic this, i use a multiply node to multiply the translucency map intensity by 4 when i put a transparency value to 0.25.

and to get a better result you can use some 3d stuco nodes to change the leaves color in a "natural" look.


this first image without stucco, like in summer


http://usuarios.lycos.es/heteropterus/imagenes/ContraluzInterior_summ.jpg


this second one with two stucco nodes to mimic the start of the autumm, only aplied to some oaks

http://usuarios.lycos.es/heteropterus/imagenes/ContraluzInterior_aut1.jpg

this with a diferent scale in the stucco nodes and some changes in the texture color

http://usuarios.lycos.es/heteropterus/imagenes/ContraluzInterior_aut2.jpg

the last with the same texture aplied to all the oaks

http://usuarios.lycos.es/heteropterus/imagenes/ContraluzInterior_aut3.jpg

[tostao_wayne]

and finally all the oaks in red

i've play with the same leaf with 3 diferent colors


http://usuarios.lycos.es/heteropterus/imagenes/ContraluzInterior_autumm.jpg

[igi]

great shot

[InfernalDarkness]

....and the renders with explanations are very helpful! Thanks for sharing.

[JayHoo]

Really great posts and descriptions. Maybe I can ad some too but I need to create some trees first of all.

royterr, in my opinion is a better way to use a Mib_twosided sample compositing instead a sampler_info. by this way you can handle two independients mia_material, one for each side, you must think that for example the bump for one side must to be the oposite for the other side...

I would not agree with you. My leaf shader is based on a condition node / sampler info setup where I am using different textures for the back- and foreground. Just put the texture in the appropriate slot.

[tostao_wayne]

Really great posts and descriptions. Maybe I can ad some too but I need to create some trees first of all.



I would not agree with you. My leaf shader is based on a condition node / sampler info setup where I am using different textures for the back- and foreground. Just put the texture in the appropriate slot.


ok, the final result is exactly the same.

[royterr]

here are my progress so far:

- i deleted the condition nodes because because what i wanted was done automaticlt by the mia_material
- improved leafs orientation so they face the sky

As you see in the last exemple we barely see the texture of the leaf due to reflection and transparency power wich kills away the diffuse value. I know that this works very well for arc/solid materials, but i am not that sure if that works well for leafs.


http://sor.typepad.com/.a/6a00d8350600cb53ef0120a5d79457970c-800wi


improved reflections:
http://sor.typepad.com/.a/6a00d8350600cb53ef0120a581f951970b-800wi

btw its unbelievable how much the shape of the tree especially leaf position is important, even if you have a perfect shader, the geometry of the tree has a very tricky role.

making a realistic tree mesh in paint effects is very flexible but a bit hard.
what are you guys using to generate those simple trees?

[redbranch1]

Tostao, those renderings are beautiful! If possible, I would love to sneak a peek at your scene file. I've never been able to get outdoor renderings with grass and trees even remotely that good looking. Well done!

[Sincrol]

i know this may sound a lil stupid but...
have someone tried some "dark green" AO on the leaves? :>



try out. :x

[yoshi95]

sorry to bring this old thread back to life, but i m just curious if anybody got new insights or better techniques for doin this using mia_material since april.....

looking at previous posts by others, it seems like the key is to make the leaf translucent enough so that when the tree is in shadow, and back lit, sun light still come through.

the problem is if i put 0.3 transparency, or even 1.0 transparency, not enough light comes through....and i boost up the mrSky multiplier 2 or 3 times to make the leaves appear more translucent. i turned down the exposure to compensate for the increased multiplier.

all the previous post helped me a lot, and i did some tests on my own. i m not sure if it is the sampling or the filtering, but my grass look blurry and muddy, instead of visible blades of grass.

while the far away trees looks ok, the close up ones looks plastic, partly due to poor modeling....

here are my results:
http://photos-f.ak.fbcdn.net/hphotos-ak-snc3/hs185.snc3/19248_248449208567_729893567_3384065_6652375_n.jpg

http://photos-e.ak.fbcdn.net/hphotos-ak-snc3/hs165.snc3/19248_248930948567_729893567_3385279_1963918_n.jpg

[tostao_wayne]

you must to use a mulptiply node for the translucence map

if you set the transparency to .25 you must to multiply the intensity of the translucence map by 4 to get a total translucence intensity of 1.


here you can find more information about it

http://forums.cgsociety.org/showthread.php?f=87&t=804892&page=12&pp=15

[yoshi95]

great thx a lot for that thread, seems like it has everything i need......just never thot of using a 2 sided material because the math sounds weird......

like 0.25 transparency, with 1.0 translucency, means 25% of light is getting inside the leaf...
with the backside mia_material having a low reflective value, say 0.2, means 20% of the translucent light gets reflected, so only 5% of actual light comes out of the leaf......... which is y i think u multiply the translucent map output value by 4, so u get 20% of the light out......

but it looks great from what others have posted......i ll definitely give it a try....

[royterr]

you must to use a mulptiply node for the translucence map

if you set the transparency to .25 you must to multiply the intensity of the translucence map by 4 to get a total translucence intensity of 1.


here you can find more information about it

http://forums.cgsociety.org/showthread.php?f=87&t=804892&page=12&pp=15

i dont understand the logic here. When you turn ON translucency (with a weight value od 1 1) then it totaly replaces the transparency. So why not just set the transprency to 1 instead of the multiply mode.




great thx a lot for that thread, seems like it has everything i need......just never thot of using a 2 sided material because the math sounds weird......

like 0.25 transparency, with 1.0 translucency, means 25% of light is getting inside the leaf...
with the backside mia_material having a low reflective value, say 0.2, means 20% of the translucent light gets reflected, so only 5% of actual light comes out of the leaf......... which is y i think u multiply the translucent map output value by 4, so u get 20% of the light out......

but it looks great from what others have posted......i ll definitely give it a try....

could you post a comparison between a steup with multiply node and one without it?

[yoshi95]

just to comment on 'y not turn transparency to 1 and skip multiply node', heres what i found on mental ray forum:


I assume you have conserve energy on, which means that mia_material will make adjustments.

First, it will determine reflectivity by your weight, and by viewing angle, (they are multiplied).
For view angle dependence settings, see BRDF section. What values are you using for a BRDF of the leaf?

Next, it will take the leftover weight (1 - calculated reflectivity), and look to see if you set transparency.
Then, that weight will be taken out of the leftover weight.

Finally, whatever is leftover after transparency, is used for diffuse, no matter what the diffuse weight is set to.

Now, transparency can itself be divided into translucence and non-translucence by the translucence weight factor.

so again if my leaf material is, say 0.6 reflective, 1.0 transparent, 1.0 translucent, this means only 40% of the light is coming through the material? and that the diffuse component is completely ignored.....which is mathematically correct, not sure bout physically correct, without truly using SSS......but simply not bright enough to be realistic looking...

[tostao_wayne]

i dont understand the logic here. When you turn ON translucency (with a weight value od 1 1) then it totaly replaces the transparency. So why not just set the transprency to 1 instead of the multiply mode.

because the translucency only acts with backlight, so when the leaf is in a front light situation it is almost opaque. the translucency has a value near to 0 * 4 = near to 0. in the link that i have posted the tree has always a translucency map value of 4, but in the front light situation, it has almost no translucency.

[tostao_wayne]

so again if my leaf material is, say 0.6 reflective, 1.0 transparent, 1.0 translucent, this means only 40% of the light is coming through the material? and that the diffuse component is completely ignored.....which is mathematically correct, not sure bout physically correct, without truly using SSS......but simply not bright enough to be realistic looking...

i'm not totally sure, but the transparency of the object is determined only by the transparency value and the angle between the camera and the surface and the BRDF, the reflectivity is more or less an aditive proces, so don't take it in acount.

[royterr]

because the translucency only acts with backlight, so when the leaf is in a front light situation it is almost opaque. the translucency has a value near to 0 * 4 = near to 0. in the link that i have posted the tree has always a translucency map value of 4, but in the front light situation, it has almost no translucency.

i have difficulty understanding this.
whats the main difference between transparancy1/ no sss mltiplier and transparancy 0.25/sss 4 multiplier?

[tostao_wayne]

i have difficulty understanding this.
whats the main difference between transparancy1/ no sss mltiplier and transparancy 0.25/sss 4 multiplier?

With transparency 1 -> leaves totally transparent -> almost flat foliage
with transparency .25 -> leaves not totally transparent -> volume foliage

but... you want a translucency intensity of 1 (near to the color that the leaf has with front light), so the only way to get this is to use a multyplier to increase the value of the translucence when the transparency is set to .25

the problem is that translucency and transparency must to be independent channels, but in mia_material, the intensity of the translucence is controled by the amount of transparency.

an example: the human skin is totally opaque but has translucence.

[yoshi95]

here r my low quality test renders with the translucency multiplier.....with 1 mia_materil, not 2 sided shader

with multiplier:
http://photos-e.ak.fbcdn.net/hphotos-ak-snc3/hs202.snc3/20948_271355678567_729893567_3469442_2650615_n.jpg


without:
http://photos-c.ak.fbcdn.net/hphotos-ak-snc3/hs202.snc3/20948_271355688567_729893567_3469443_7643154_n.jpg



it s an improvement......maybe denser grass and better trees....

[Hamburger]

Another thing that's really important is to have more than 1 leaf type per tree! (ie three leaf shaders per tree)

http://kiernanmay.net/wp-content/uploads/2009/12/farnsworth_v14.png

http://kiernanmay.net/wp-content/uploads/2009/12/farnsworth_v14_3.png

Not 100% necessary....but if you don't (unfortunately I didn't with this rendering test I did) you can tell each tree individually and it is not as realistic!

I'm still interested in Alessandro's leaf shader workflow! ;)

[tostao_wayne]

here r my low quality test renders with the translucency multiplier.....with 1 mia_materil, not 2 sided shader

with multiplier:
http://photos-e.ak.fbcdn.net/hphotos-ak-snc3/hs202.snc3/20948_271355678567_729893567_3469442_2650615_n.jpg


without:
http://photos-c.ak.fbcdn.net/hphotos-ak-snc3/hs202.snc3/20948_271355688567_729893567_3469443_7643154_n.jpg



it s an improvement......maybe denser grass and better trees....

i like how it looks with multiplier, are you ussing mia_exposure_protographic?? if not, try it

[tostao_wayne]

Another thing that's really important is to have more than 1 leaf type per tree! (ie three leaf shaders per tree)

http://kiernanmay.net/wp-content/uploads/2009/12/farnsworth_v14.png

http://kiernanmay.net/wp-content/uploads/2009/12/farnsworth_v14_3.png

Not 100% necessary....but if you don't (unfortunately I didn't with this rendering test I did) you can tell each tree individually and it is not as realistic!

I'm still interested in Alessandro's leaf shader workflow! ;)


impresive Hamburger, i like it :beer:

totally agree with you, its really important to have more than 1 leaf type per tree, one solution for it is to use some stuco nodes and plug diferent shaders in each channel.

i'm interested too in Alessandro's leaf shader workflow

[InfernalDarkness]

Don't know if you're using Onyx for your trees, but if so you can specify how many different leaf objects you need in the export dialogue. This makes texturing much easier, and I usually try to use at least two different leaves as well, if not more for foreground trees.

[JohnPetrucci]

I have a noob question
where do you plug the multiply node into the mia material translucency options. is it the color or the weight?

[tostao_wayne]

I have a noob question
where do you plug the multiply node into the mia material translucency options. is it the color or the weight?

the color, the weight always to 1.

[yoshi95]

in the other thread u posted ur leaf textures, i m wondering how did u get the leaf to look very diffuse lit.

all the leaf texture i found from google has specular highlights, which i dont really want.

on a 2nd look are your leaf texture hand painted?

[tostao_wayne]

in the other thread u posted ur leaf textures, i m wondering how did u get the leaf to look very diffuse lit.

all the leaf texture i found from google has specular highlights, which i dont really want.

on a 2nd look are your leaf texture hand painted?


they are scanned, with a white background (some A4 papers (4 or 5)), but without to close the scanner.
The intention was to get a more or less plain leaf but not totally plain.

[JohnPetrucci]

in the other thread u posted ur leaf textures, i m wondering how did u get the leaf to look very diffuse lit.

all the leaf texture i found from google has specular highlights, which i dont really want.

on a 2nd look are your leaf texture hand painted?

just hand paint them man, it will look a lot better and you can actually put detail where you want to.
and if you're not good at painting then there're a few photoshop filters that flatten the color, I think it's called High pass or something like that.

[yoshi95]

i will probably end up hand painting them, since i dont have a scanner, and it s hard to find several different leaves that are front facing and diffuse lit online.

so back to the texturing part........the mib_twosided shader, here r my thots.....i dunno which way is better in terms of realism/speed

config1 (it seems i can only do this in maya, i cant plugin a mia_material in the top/btm slot in max, cuz it s a map):
mib_twosided shader:
top --> mia_material for top leaf side ( includes top diffuse, bump, translucency, reflectance map)
bottom --> mia_material for bottom leaf side ( includes btm diffuse, bump, translucency, reflectance map)

config2:
mia_material:
diffuse: mib_twosided with top/btm img
reflection: mib_twosided with top/btm img
etc....

sounds like i m stuck with option 2 in max

[tostao_wayne]

i will probably end up hand painting them, since i dont have a scanner, and it s hard to find several different leaves that are front facing and diffuse lit online.

so back to the texturing part........the mib_twosided shader, here r my thots.....i dunno which way is better in terms of realism/speed

config1 (it seems i can only do this in maya, i cant plugin a mia_material in the top/btm slot in max, cuz it s a map):
mib_twosided shader:
top --> mia_material for top leaf side ( includes top diffuse, bump, translucency, reflectance map)
bottom --> mia_material for bottom leaf side ( includes btm diffuse, bump, translucency, reflectance map)

config2:
mia_material:
diffuse: mib_twosided with top/btm img
reflection: mib_twosided with top/btm img
etc....

sounds like i m stuck with option 2 in max

if you use the second method you will must to use a map for every value that change form one side to the other, from my point of view too much maps, and a very confuse shader network

[royterr]

after reading all this thread again, it's still very hard to obtain leaves like prodan's renders.
to resume things most of us are using those 2 things

1-you need a realistic tree model with sky sensitive leaves (from Onyx or Paintfx or other good software).

2-a mia_material with those settings:
diffuse weight:1
reflectibity: 1
glosiness 0.2/0.5
thin walled
fresnel reflection
ao color bleed
transparency 0.25 (compensated in the translucency color by multiply node *4)
transparency glosiness 1
translucency weight 1

again even with those values, we are still very far from realistic leaves/trees.

[InfernalDarkness]

I believe your mia_material_x settings are a bit off. Why would a leaf's reflectivity be 1? And not all leaves have the same transparency; setting that to .25 seems to have no physical basis in reality. Play with the numbers to make your leaves proper. Also, a leaf wouldn't have Fresnel falloff; that's more for glass/liquids.

http://img685.imageshack.us/img685/2356/tiliafluidskymr4web.jpg

[royterr]

yes the reflec value is 1 but i have a reflection color map close to graythat drives the overall value so there is no 100 part reflective part on the leaf. plus u need some glosinnes.
i agree that leafs shouldnt have a fresnel falloff i am using these values here :0.001/1/1.5

now i want to make things clear for the sss textures and sss values (wich are driven by the transparency value): here is some comparisons:

http://sor.typepad.com/files/sss_transp_values_comp.jpg

full resolution
http://sor.typepad.com/files/sss_transp_values_comp.jpg

*i dont know if you guys noticed but when the directional sun (direct light) is turned off, sss effect becomes very weak on the leaves (specially the back).But in Prodan's 4th render:
http://marlas.cgsociety.org/gallery/ it seems that even with no direct ligh, the sss effect is pretty strong,
notice the branch hanging in the middle of the foreground, it's in the shade but the sss is pretty noticeable. I really wonder how this has been done.

*by sss texture i am refering to the translucensy texture.

[InfernalDarkness]

Those look great, Royterr. Curious why you're not happy with your various results? I can see some of those leaves looking great in certain scenes, and some of them looking great in other scenes...

Anything else you were trying to achieve?

[royterr]

Those look great, Royterr. Curious why you're not happy with your various results? I can see some of those leaves looking great in certain scenes, and some of them looking great in other scenes...

Anything else you were trying to achieve?
the results are pretty promessing so far but not photorealistic.
i will stop when you coudnt tell if its a photo or Mr4Maya render.

now i made these tests so we could all agree on mia_material values.
we all agree on most of the values (diff bump reflec ao) regardless of the top/botoom tetxures.
it seems that the transparency value in most cases is 0.25 to 0.3 max.
the translucency must have a 4 multiplier in the direct light and more than this in the shade.

[TaKIKO]

I think what you got is fine you just need to push it more in post. I played around with it a little in nuke and imo it looks a bit more real. Ima write more tomorrow I super tired and need sleep.
my version is on the left
http://img59.imageshack.us/img59/7218/treecompcopy.jpg

[InfernalDarkness]

No offense, Royterr, but no two people will agree on photorealism generally if they know it's CG. I think your tree renders are great, but without a scene or background involved they're always gonna look CG. Quality-wise, they're perfect.

As for settings we can all agree on, that also will never happen! And most plants are VERY different. One species' settings will differ from another, sometimes vastly. Unless you plan on taking photometric measurements of light transmittal through every kind of plant available, at ever phase of their life-cycle, you're stretching too hard here. Just find settings that work for the scenes you need 'em for! I don't believe there are any universal settings, and I don't even use SSS for most of my work. I like some of yours better, but not enough to say (for example) that all plants need SSS to be "photorealistic".


Your trees look great my friend!

[TaKIKO]

Infernal Darkness pretty much said what I was going to say. Your work is always going to look "cg" when against a flat background and no scene. You have all the surface properties in your leaves everything looks right I just think you need to create more realistic setup other then the bush agsinst a blue wall. The renders you see from prodan's work I'm pretty sure had to some extent post work: color correct,grades,chromatic abberation,bloom,etc.

[royterr]

i perfectly agree with both of you on these points.
i know that generaly depth of field/motion blur/chromatic aberration/film grain tend to give the image that last 10 percent of reality.
But i like having a strong photorealistic base before going to post (even in front of a gray background). I usually proceed from the ground up so each element must be 99 percent photorealistic (in my eyes) before proceeding.
Anyway i am going to try to push the shader just a bit further before moving on with the rest.

*Michael i like your CA effect, did you move the rgb channels or is it a filter?

[TaKIKO]

For the aberration I used this gizmo (http://www.creativecrash.com/nuke/downloads/gizmos/filter/c/akromatism-st-rub-chromatic-aberration--2). I agree with you about trying to get the raw render to look as real as possible, I am this way too but what I have begun doing (on personal projects) is when my shaders are close to done I take renders into nuke and do some post work to see how they look. I my self can be very anal and picky about getting my shaders correct and as real as possible but as I began to learn more about compositing/color corrections you tend to save yourself time when it comes 3d vs 2d tweaks. I think your leaves are just as good as those renders from prodan, you have all the correct surface qualites of a leaf. But in my opinion what makes his more realistic is just the shear amount of leaves he has and and as I said before his color grades/corrects,post,etc.

[Spacelord]

Jeff Patton recently did a nice tut on Translucency, his trick is to use the translucency lume shader.
So if maya has that you should be able to do the same.

http://jeffpatton.net/openb/index.php/2010/05/26/translucent-leaves-in-mental-ray

[Eshta]

Jeff Patton recently did a nice tut on Translucency, his trick is to use the translucency lume shader.
So if maya has that you should be able to do the same.

http://jeffpatton.net/openb/index.php/2010/05/26/translucent-leaves-in-mental-ray

I don't think Maya has it, but when I installed mental ray standalone 2011, I noticed the dll file in the install directory. so i guess you can use that

[amitkhanna]

Mrguy, you are right, i am using the gamma correct node because i am using a 2.2 gamma value in my mia_exposure_simple.So you have to correct everything, even color swatches ( i am not sure wether you have to gamma correct the "Ambient Shadow color" in the AO section)

As for the condition node, its very simple: you have a sampler info node that's inputing information about the normals and it's plugged to the first term of the condition node. and the condition node sees if the condition is availables ( so normal fliped) so if "color if true" has a white value (0 0 0) and "color if false" a 0.35 gray value.

I will post some more renders with better trees soon.

Hi there,

I was reading your post regarding gamma correction as you have 2.2 gamma value in mia_exposure_simple.

But for leaf color or translucency files cant we just increase the color gain value higher than 1. I tried both, Using the gamma correction node and the color gain value... for 2.2 gamma correct value... a value of around 1.7 color gain gave me very similar effect...

So I am wondering what I am doing is fine or am I missing something ? Kindly advise :)

cheers,
ak

[royterr]

Hi there,

I was reading your post regarding gamma correction as you have 2.2 gamma value in mia_exposure_simple.

But for leaf color or translucency files cant we just increase the color gain value higher than 1. I tried both, Using the gamma correction node and the color gain value... for 2.2 gamma correct value... a value of around 1.7 color gain gave me very similar effect...

So I am wondering what I am doing is fine or am I missing something ? Kindly advise :)

cheers,
ak

just use a gamma of 2.2 ans use a gamma correct node of 0.45.

[royterr]

i'm statisfied with my leaves so far, from now on it's all about finding a descent tree geometry (wich is really hard to find) to achieve a convincing organic image.I hope maya 2012 will include nice paint effects preset trees.

I am running short on time, i will pass to the grass shader now, i am satisfied with the short grass shader below, i will soon focus on medium,high grass (paint effects).

http://sor.typepad.com/.a/6a00d8350600cb53ef013485ed49cb970c-pi

[kiryha]

Very nice renders, royterr. Very nice.

[royterr]

Very nice renders, royterr. Very nice.

thanks alot man.Glad u liked it!

[InfernalDarkness]

It's wonderful to see your progress, Royterr! Your plant work is top-notch now, a bit jealous here... Still struggling for photorealism on some projects.

What I'm running in to now is implementation. Perhaps this question belongs in the other thread, though... How to go about making a library of all our plants?

As for biological accuracy, so far Onyx is the best I've found. Arbarro is close. But it's a really limited selection, and I'd love to help work on something more powerful/effective if anyone else is interested.

[royterr]

It's wonderful to see your progress, Royterr! Your plant work is top-notch now, a bit jealous here... Still struggling for photorealism on some projects.

What I'm running in to now is implementation. Perhaps this question belongs in the other thread, though... How to go about making a library of all our plants?

As for biological accuracy, so far Onyx is the best I've found. Arbarro is close. But it's a really limited selection, and I'd love to help work on something more powerful/effective if anyone else is interested.

thanks alot man!

i totaly agree with you on Onyx trees (the renders are onyx trees).
but the convincing trees in the whole onyx library are just a fiew.
as for the grass implementation, its all about how you lay down your patches: big patches layed out manually or small patches painted over a big surface (paintfx paint/geometry paint/custom paint) i dont like the last one because it causes alot of grass geometry interpenetration.

[TinyCerebellum]

Your leaves do indeed look fantastic, royterr. Very nice job.
For the grass I found the same thing, that painting patches on the surface tends to cause too much interpenetration. A solution with the paint script is to use circular grass patches, and set the offset value appropriately.

[royterr]

Your leaves do indeed look fantastic, royterr. Very nice job.
For the grass I found the same thing, that painting patches on the surface tends to cause too much interpenetration. A solution with the paint script is to use circular grass patches, and set the offset value appropriately.

thanks alot man!
even with a circular grass patch (with offset), u will end up with alot of interpenetrated blades.
ideally one would choose a big surface and paint it with a huge pfx brush (one stroke) and ajdjust the blade scale, but thats not possible (unlike onyx grass generation) because the pfx mesh options has triangle limit option.
so the best solution so far is to generate the biggest patch u can in pfx and duplicate it but this method has its own limitation, since a big brush cant follow a curved surface.

[royterr]

http://sor.typepad.com/.a/6a00d8350600cb53ef01348640d3f1970c-800wi

medium damaged grass

[Hamburger]

Did you use the stucco node for that? Looks good

[royterr]

Did you use the stucco node for that? Looks good

fractal, easier to control.

[royterr]

Almost there.

full res (http://sor.typepad.com/files/untitled-4-1.jpg)

http://sor.typepad.com/files/untitled-4-1.jpg

[Undseth]

Nice!

I wonder if the grass will look as good/realistic as that when viewing it from afar.

[Mrguy]

Wow looking really good royterr!

I was trying to do some tests with grass in vray recently and was somewhat happy with the results. But what your achieving is really really nice. Makes me wish I spent a little bit more time in mental ray.

[royterr]

Nice!

I wonder if the grass will look as good/realistic as that when viewing it from afar.

i totaly agree, i still dont get why the midground and teh background always look less convincing the the foreground.

Wow looking really good royterr!

I was trying to do some tests with grass in vray recently and was somewhat happy with the results. But what your achieving is really really nice. Makes me wish I spent a little bit more time in mental ray.

how did you create your grass in vray, is it convincing?

[JohnPetrucci]

looking good roytter!! how did you do that grass? was it paint effects with mia material for the shader?

[royterr]

looking good roytter!! how did you do that grass? was it paint effects with mia material for the shader?
exactly. 1 large paint effects brush.

[mthemelis]

Roytter,

how did you render this perfect grass? MR / Vray (polys) or Maya SW / RfM (pfx)?

thanks in advance
mike

[royterr]

Roytter,

how did you render this perfect grass? MR / Vray (polys) or Maya SW / RfM (pfx)?

thanks in advance
mike

paint effects converted to polys and rendered in mental ray.

[kiryha]

Roytter, did you try to render some animation?
I have strong flickering in translucency pass and i can`t figure out the reason why its happen.

[royterr]

Roytter, did you try to render some animation?
I have strong flickering in translucency pass and i can`t figure out the reason why its happen.

you have to increase your gloss/reflec samples + FG rays/interpolation and you should be fine.
can you post an animation to see the problem?

[visua]

http://sor.typepad.com/.a/6a00d8350600cb53ef01348640d3f1970c-800wi

medium damaged grass

Nice work royterr, can I ask how do you hook up the fractal to get the color-variation, to the color-gain or?

[royterr]

Nice work royterr, can I ask how do you hook up the fractal to get the color-variation, to the color-gain or?

just make a layered texture and use the fractal as a mask.

[royterr]

final grass for production:
http://sor.typepad.com/files/grassg.jpg

full size (http://sor.typepad.com/files/grassg.jpg)

[Undseth]

Aah, I like this. Like, a lot. :applause:

royterr, I wonder have you tried rendering the grass with the camera looking simply downwards?

[visua]

Got a question for ya guys, I tried this nifty approach at work in max and I felt pretty happy with the results. But, I don't seem to be able to recreate the same thing in maya?

Mapping the translucency-weight, check, problem being of course that when the weight
gets lower then 1 then your leafs start to get well transparent. The solution is to hook up a mib_two_sided to the transparency with a bitmap connected to the back-slot, and that should take care of the transparency-problem. Works fine in max but apparently not in maya, any takers?

It should be possible to actually map the translucency-weight no?

http://3dsmaxrendering.blogspot.com/2008/06/translucent-leaves.html

[InfernalDarkness]

Mapping the translucency-weight, check, problem being of course that when the weight
gets lower then 1 then your leafs start to get well transparent. The solution is to hook up a mib_two_sided to the transparency with a bitmap connected to the back-slot, and that should take care of the transparency-problem. Works fine in max but apparently not in maya, any takers?

Use a multiply/divide node and multiply your translucency by 4. The transparency of your grass or leaf mia_x should be no greater than .25.

[visua]

Use a multiply/divide node and multiply your translucency by 4. The transparency of your grass or leaf mia_x should be no greater than .25.

Yeah that's the workflow I usually go with, just wondering why the setup Remy uses should'nt work with maya? ;)

[MasonDoran]

It does, just connect the mib_twosided result to the refr_trans_weight

you could then connect another to the translucency color

You will probably need to make sure the geometry is double sided and the shader has "thin walled" on

[visua]

It does, just connect the mib_twosided result to the refr_trans_weight

you could then connect another to the translucency color

You will probably need to make sure the geometry is double sided and the shader has "thin walled" on

Tried that one, doesn't seem to matter what I plug where I still don't manage to solve the transparency-issue that Remy does by:

"For the back I wanted the translucency to be strong so the value of the transparency is on and controlled by a gray-scale map of leaves. This keeps the leaves from being transparent."

[MasonDoran]

Just use more twoSided shaders.

MIA shaders need to have transparency on for translucency to work. If things start to look TO transparent, lower the refraction gloss.

So connect the outA of a twoSide shader to the transparency. Connect another to the color, and a third to the Weight.

That will completely isolate the two sides so you can treat them as seperate surfaces.

Dont forget that Black translucency color is essentially turning it off.

[living3d]

ideally one would choose a big surface and paint it with a huge pfx brush (one stroke) and ajdjust the blade scale, but thats not possible (unlike onyx grass generation) because the pfx mesh options has triangle limit option.


I think you can exceed poly limit restricted by 1 million in "paint effects to poly" option dialog. In the strokeShape node in Mesh Output rollout you can change poly limit.

[InfernalDarkness]

Quote:
Originally Posted by royterr
ideally one would choose a big surface and paint it with a huge pfx brush (one stroke) and ajdjust the blade scale, but thats not possible (unlike onyx grass generation) because the pfx mesh options has triangle limit option.




I think you can exceed poly limit restricted by 1 million in "paint effects to poly" option dialog. In the strokeShape node in Mesh Output rollout you can change poly limit.

Set the poly limit to 0 for no limit.

[Kinematics]

Guys, I know this information is somewhere on the forum but i tried googling and stuff but can't really find the answer any more though I know I skimmed by it once.

I am testing out this stuff on Vray 1.5 so if you have information specific to that it would be great but I guess it would work either way.

How do I go about assigning different textures or shaders to create variety. Isit with the ray switcher? Is there an easy way to do this?

I am using proxies which are then instanced across. I aint good at mel so I am hoping there is a simple solution. but if there isnt. do just tell me where to look. ill figure it out. thanks guys

[InfernalDarkness]

Try this section of the forests in mental ray (http://forums.cgsociety.org/showthread.php?f=87&t=804892&page=12&pp=15) thread. It's dealing not with MR actually, but with UV-maps for multiple leaves in one shader.

Tastao_wayne has some excellent inside into this topic. He runs a script, which he wrote, which separates all your leaves into a 3x3 UV set. This lets you use 9 different leaf textures per tree, basically. I've not used this script yet but his results are astounding - best I've ever seen, by a pretty large margin even.

This post specifically (http://forums.cgsociety.org/showpost.php?p=6180444&postcount=177)delineates his technique.

[slam-k]

http://www.djx.com.au/blog/2009/03/04/mifinalgatherhide/#more-130
this should be helpful to understend how light pass through the sufrace of leaves so deep, i think.
sry for my bad english

[Dangertaz]

Am I correct in assuming that the color variations (some patches are yellowish while others are a bluer green) is being driven by the Fractal? If so could someone please explain how exactly the Layered texture with a fractal mask is being set up and used in the MIA? Or is this really 5-6 different MIAs with the color shifted in each one?

Thanks in advance








just make a layered texture and use the fractal as a mask.

[syna]

Am I correct in assuming that the color variations (some patches are yellowish while others are a bluer green) is being driven by the Fractal? If so could someone please explain how exactly the Layered texture with a fractal mask is being set up and used in the MIA? Or is this really 5-6 different MIAs with the color shifted in each one?

Thanks in advance

You can use the fractal conected to a blend colors node.

[Dangertaz]

I can see how that would affect the color on each individual grass blade but based on what I'm seeing in posts # 95 and 97 it appears to be modifying the color of grass patch as a whole. If this is true, I wonder what shader network connects are necessary to modulate the color of a huge grass patch from brown to green using a fractal as a mask(or just a blend color node)?

[m0z]

I'll give you one example how I did it las time.
Create a low saturated diffuse texture for the grass and put it -well in the diffuse channel.
Connect a ramp/noise/whatever as projection (right mouse button in hypershade by creating the node) in Y direction into the colorgain channel.
Resize it to group bounding box.
Now you're obviously able to change the hue of the grass based on your planar mapping.
Voila.

One could also make a y-planar UV snapshot and paint the whole color texture in photoshop for mapping purposes.


Basically that's how I managed to colour a huge field of binaryproxy patches - all attached to the same MIA shader - like a football field.

[slam-k]

http://img21.imageshack.us/img21/584/04forest.jpg
In this image we can see how light passes through the leaves gently and gradually fades.
With the use of translucency we do not get this effect... as with the use of refraction. How can we to achieve this effect? without direct light, only for mr sky. I spend many time working on this and I still far... I try to reconnect shadow node for mia material, on mib_shadow_transparency. Then I reduce the color of transparency... this works but not properly. So i stuck... any ideas?

Sorry for my bad english

[slam-k]

http://img651.imageshack.us/img651/9584/88423691.jpg (http://imageshack.us/photo/my-images/651/88423691.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

this is what i've got... but only with mia_protal

[InfernalDarkness]

@slam-k: That render looks cool, but it not a realistic light transmission example at all. The second and third planes down appear to be as bright as the top one; there are some materials which may react this way, but vegetable (leaf) matter does not. If you take a length of string and say, ten actual leaves in real life, and dangle them roughly the same space apart along the string, and then hold them up in the sunlight, you see nothing like what you've rendered here. Granted, as you space the leaves closer together, you'll get more occlusion of course, and light transmission is certainly species-dependent...

But most of this can be handled automatically using Final Gather itself. Here are some examples:

10 leaves, area spotlight (disc), 1 secondary FG bounce:
http://img51.imageshack.us/img51/8193/fpleaftestmr3spotarea.jpg

10 leaves, sun/sky, 0 secondary FG bounces:
http://img202.imageshack.us/img202/3290/fpleaftestmr4sunfgnosec.jpg

20 leaves, sun/sky only, no secondary bounces:
http://img41.imageshack.us/img41/6057/fpleaftestmr5sunfgnosec.jpg

20 leaves, spotlight w/photon GI & caustics for comparison:
http://img694.imageshack.us/img694/1270/fpleaftestmr6spotphoton.jpg

slam-k http://img21.imageshack.us/img21/584/04forest.jpg
In this image we can see how light passes through the leaves gently and gradually fades.
With the use of translucency we do not get this effect... as with the use of refraction. How can we to achieve this effect? without direct light, only for mr sky. I spend many time working on this and I still far... I try to reconnect shadow node for mia material, on mib_shadow_transparency. Then I reduce the color of transparency... this works but not properly. So i stuck... any ideas?

Translucency only plays a role if you're viewing the underside of the leaves. It has nothing to do with the transmittal of light, in the mia_mat_x. The refraction transparency strength however does affect the transmittal of light, and also the settings "thin walled/solid" and "refractive caustic/transparent shadow" affect the look tremendously. You don't need an mib_shadow_transparency node at all if you're already working with the mia_mat_x.

What you're seeing in the render you posted there of the trees is the Final Gather filtering in effect really. The darks are more precise with a filter of 1, and the lights too. If you're rendering with a filter of 0 (default), you'll never really get this contrast, which is mostly geometry-based and not based on the shaders so much. You cando the same thing with Blinns or Phongs and get similar results, so long as your geometry and foliage is dense enough.

My point being, in your lit planes render example, leaves do NOT act like this at all. The second and third leaves in will be reasonably darker than the first, not bright white. And subsequent leaves will still be lit partially due to the indirect lighting of the Final Gather calculation; this is where you can adjust the depth using FG scale if you like, the filter settings, and of course how many secondary bounces you want to see.

[slam-k]

thanks for the detailed response. Very usefull info for me.

Another thing I cant understand is - how leaves can at the same time pass light in some place, and block in other?

http://img7.imageshack.us/img7/3928/12selva.jpg

Look at this image, where leaves pass light with such force, that they become pale green.
How can it be? I cant understand this. and there is another problem driving me crazy... why shadows under house completely black? This is AO post processing?

[ytsejam1976]

DOn't take the image as render image, More post in the images, so post effects is your help.

and no post effects like render passes or layer AO. Only exr 32 bit AE in post.

[royterr]

http://img21.imageshack.us/img21/584/04forest.jpg
In this image we can see how light passes through the leaves gently and gradually fades.
With the use of translucency we do not get this effect... as with the use of refraction. How can we to achieve this effect? without direct light, only for mr sky. I spend many time working on this and I still far... I try to reconnect shadow node for mia material, on mib_shadow_transparency. Then I reduce the color of transparency... this works but not properly. So i stuck... any ideas?

Sorry for my bad english

prodan never said that he didnt use an area light above those trees to accentuate the indirect sky light.

[slam-k]

Ye i thought about that... i used portal light with mrsky but this never worked out for me.

I need to get reflection with glossy highlights on the grass. How can i achive seenable glossy reflections on it? Its either reflects far too much or just doesnt at all ,despite parameters of BRDF i used. I use only mrsky without sun and photographic exposure control. When i use portal light theres no changes on image.

[ytsejam1976]

Sorry but where you put your portal light?
On the Windows right?

Exposure settings are simple. Burn higlight 0.8 and what value you prefer on iso shutter and stop. :)

You say, use only sky without sun. but this is plausible on vRay not mental ray. In mental ray for get nice effects you must use Environment built IBL in light mode. Complicated, more complicated and unusable, for my experience. IT's slowwwwwwwwwwwwwww.................
In Vray it get nice result only skymap on DomeLight and a direct light disable, but used only for the direction work of the sun in the sky.
On forest maya mental ray thread inside this section of the forum, see and get nice helpfull tips, for your grass.

[slam-k]

Actually its an open world enviroment so theres no windows. =)
I used portal light as main light source, and still theres no reflections.But when i raise literally speaking preferences of BRDF to unbelivable heights they appear and still its not what i want.

Ive took a look at the topic even before you said , many times actually.Useful.

[royterr]

Actually its an open world enviroment so theres no windows. =)
I used portal light as main light source, and still theres no reflections.But when i raise literally speaking preferences of BRDF to unbelivable heights they appear and still its not what i want.

Ive took a look at the topic even before you said , many times actually.Useful.

for the highlight u just need too boost the glosiness of ur mia_material and make sure ur blades have a bit of curvature. Keep in mind that for leaves and grass what makes it believable is mostly the geometry and not the shader, some grass /leaves in the real world are completely matt with translucency.

[slam-k]

royterr ye i know about this.

Prodans grass reflects alot but the grass is at a slight angle... When I add a reflection to the grass, almost do not see the highlights.

[InfernalDarkness]

Keep in mind that for leaves and grass what makes it believable is mostly the geometry and not the shader, some grass /leaves in the real world are completely matt with translucency.

I disagree entirely regarding believability. The geometry for leaves especially is irrelevant - it's all about the shader. With grass, the geometry can be very simple and basic and look great with a decent shader, or be very complex and high-poly and look horrible with poor shading. Also, Final Gather plays a huge role in realism for mental ray - both the quality and the occlusion effects which we've been discussing here. I'll post a pair of renders tonight that illustrate this point, when I get back home.

[Gabba]

A little test, done in Softimage 2012 SP1, rendered in mental ray (hope you guys let me post here too!). Grass instanced using ICE (the same patch repeated nearly 4000 times). I also instanced the pebbles (those are not modeled geometry, simply "standard" sphere particles, scaled in Y axe).
Tell me what do you think =)

http://img269.imageshack.us/img269/243/prova3ix.jpg (http://imageshack.us/photo/my-images/269/prova3ix.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)
http://imageshack.us/photo/my-images/269/prova3ix.jpg/

[Archi-God]

I've been following the thread for a while trying to achieve a result such as Alessandro's - I spent much time trying to do so but unfortunatley I cannot come close to this result directly from rendering, only in post with some EXR editing and exposure and gamma adjustment I can. Is there a way I can achieve this result directly or is it must to achive it in post? anyways, here is my raw rendering of a tree, and an adjusted version then I composed it with Alessandro's original render so I can compare my results and it blends quite nicely.
P.S: the tree is in the far righ corner
plz if u have any suggestions let me know
http://img717.imageshack.us/img717/3766/treeoriginal.jpg (http://imageshack.us/photo/my-images/717/treeoriginal.jpg/)
Original Rendered Raw Image
http://img853.imageshack.us/img853/5082/treejx.jpg (http://imageshack.us/photo/my-images/853/treejx.jpg/)
Uploaded with ImageShack.us (http://imageshack.us)
Adjusted & Gamma Corrected Image
http://img845.imageshack.us/img845/7774/04forestedit.jpg (http://imageshack.us/photo/my-images/845/04forestedit.jpg/)
Uploaded with ImageShack.us (http://imageshack.us)
Composited tree in Allessandro's original Image

[InfernalDarkness]

I think your leaves look fine, from a rendering standpoint. From a modeling perspective though, they aren't sky-sensitive, and most plants surely are.

Postwork and composition is the other 50% of the battle. I've had plenty of nice renders out of Maya directly, and you can get close, but if you want the stylized look like other people often present to us, gonna have to do a lot in postwork anyway. And it's way faster to control things in post than it is to re-render constantly, too!

[DutchDimension]

I can tell from your ungraded render that your Colour Management settings are wrong. Before you proceed any further, you should look into a few of the better Linear WorkFlow threads here on CGTalk to learn more about this and how to set up Maya's CM settings properly. It can be a confusing subject, but it's a very important one and is fundamental to creating a photorealistic image.

[TheNeverman]

ditto
also looks like you have an issue with your alpha mask on the leaves...


I can tell from your ungraded render that your Colour Management settings are wrong. Before you proceed any further, you should look into a few of the better Linear WorkFlow threads here on CGTalk to learn more about this and how to set up Maya's CM settings properly. It can be a confusing subject, but it's a very important one and is fundamental to creating a photorealistic image.

[wizzackr]

ditto
also looks like you have an issue with your alpha mask on the leaves...

agreed - any idea what could be causing this, though? I remember running into this problem myself a couple of times and never found out what it was. changed file formats (tga, tiff) and bit depths (8, 16 and 32bit) but remember never getting rid of the pesky white-ish borders... It even was there when I offset the alpha map in photoshop a couple of pixels to the inside.

[m0z]

I tend to set the filter on the cutout opacity texture to "none" instead of mipmap or quadratic... looks sharp and correct if the alpha is good.

[Archi-God]

Is there a way to have sky snesetive leaves in Xfrog??

[wizzackr]

I tend to set the filter on the cutout opacity texture to "none" instead of mipmap or quadratic... looks sharp and correct if the alpha is good.

Hey moz, remember doing that but i am sure that didn't fix the problem. will have to dig up a scene where we had the problem...

[m0z]

isn't it just a premultiply issue in your case? Did you turn it off?

[Dangertaz]

I use the texture maps that come with Onyx and I have this issue too! One thing I noticed is that the backgrounds for the Onyx textures are pure white while in a lot of online tutorials the background color relates the leaf, e.g. a green leaf will have a green background (as opposed to pure white). Could this be why?

[DutchDimension]

I use the texture maps that come with Onyx and I have this issue too! One thing I noticed is that the backgrounds for the Onyx textures are pure white while in a lot of online tutorials the background color relates the leaf, e.g. a green leaf will have a green background (as opposed to pure white). Could this be why?

Yes, that is part of the reason. If you find that your colour textures are surrounded by white, the best thing you can do is get rid of it, ideally by edge extending the border colour of the UV layout. The filtering in the file-node essentially tells the renderer to sample right up to and over the border by an x amount of pixels in the texture to arrive at an adequately sampled pixel to render. If outside of the UV layout is filled with an alternate colour, that colour pollutes the final colour of the pixels rendered at the edges of the leaf. Hence the ugly white edges. So essentially the unused UV space outside of the border should match the leaf colour as closely as possible.

[m0z]

Also for testing I would simply throw both files in photoshop an check the alpha out if it's 100% correct. With filter = off there cannot be any white border if the alpha is correct. :lightbulb

[InfernalDarkness]

For the sake of reference, here is the texturing method used by the master (Tastao_wayne) from the Forests for mental ray (http://forums.cgsociety.org/showthread.php?f=87&t=804892&page=12&pp=15) thread, specifically this post (http://forums.cgsociety.org/showpost.php?p=6180444&postcount=177).

http://usuarios.lycos.es/heteropterus/Hojas_Roble_haz.jpg

The cutout files are different of course, but note the subtle color bleeding around all the leaves here. Thus, when any filtering issues occur, it returns an edge colored to match the leaf, not a white outline. Works pretty well!

I generally use a mipmap filter of .2 strength on most texture nodes, but for cutouts and bumps usually none.

[m0z]

yeah and the leaf textures over here [http://www.3dmd.net/gallery/index-22.html] are like that too. Which are great btw.... fyi :thumbsup:

[ColonelMillerSG21]

I´m creating a photorealistic banana tree at the moment, but i have my problems with the lighting and the colors. I made video all of my settings and textures so that you can see what my problems are: http://www.youtube.com/watch?v=mgr1AoEM8ME

[InfernalDarkness]

@ColonelMillerSG21:

A couple things... But thanks for the video! Really sums things up much better than back-and-forthing our questions about your settings.

1. I think it may help in the long run to set up a Blinn first for all your stuff like this, so you can see in your Viewport how it's looking a bit better. Attach your mia_mat_x in the shading group like you are, but you'll have Viewport visibility which can help pre-correct color issues sometimes. Just my flow, obviously you don't have to do this and it won't affect your mental ray rendering...

2. Your cutout opacity map should be a standalone image map for easier diagnosis. It appears you have it connects to an alpha channel in one of your image files? Chances are, there are some dark but not-quite-black sections in this image causing this. If it's clean, in the File node color rollout check "Alpha is luminance" and maybe that will help? Turn off filtering for that file node, perhaps?

3. Are you using Fresnel falloff, for your BRDF? Probably should be, but if that's not working well for you then try tweaking the BRDF manually. Alternatively, you can use Fresnel with very high IOR in the Refraction section to define and brighten up reflections.

4. Is it too reflective? This may be a result of your image map going into the reflectivity channel. Try disconnecting the map and using a Reflectivity of .4 or so, glossiness around the same, to dull up those highlights. Or did you mean it wasn't reflective enough?

I think it looks pretty good, personally!

[ColonelMillerSG21]

1. Thanks, this works very good :)

2. I had the same probleme with 4 different alpha maps (mixed psd and also alpha maps without color information). I tried "Alpha is luminance" before, but that doesn´t work too. But the anti aliasing tip works, thank you very much for that :)

3. Yes. I try the refractive tweaking.

4. No, i´ve tried that before. The color and brightness of the leaf is the same:

[InfernalDarkness]

Do you have access to the image file itself? (I'm assuming you do...) If so, maybe just dial down the brightness and contrast a bit in Photoshop or something? I have to do this to my wood textures all the time, to match clients' existing kitchen cabinetry, for example. I also did this with some flowers last night. Sometimes it's nice to have that kind of control, too - update one file and control all the related nodes in Maya, obviously.

The leaf's diffuse does seem a bit washed out... It appears you're doing it all linearly, but my next question... If so, are you also using the Render Setting's "Color Management" too? If you're using that, you don't need the gamma correct node in this leaf's network at all. That check-box covers all file textures.

What connection are you gamma-correcting in this network? The reflection, or just the diffuse color? If you're using file textures, you shouldn't have to gamma-correct any connections (so long as Color Management is enabled.) But I'm really not the expert on linear lighting. Hope one of these ideas helps.

[ColonelMillerSG21]

ColorManagment! That was the crucial missing point. Now the view of the Textures in PS compares a little bit better with the final render.
http://imageshack.us/f/441/bananaj.jpg/

[ColonelMillerSG21]

It looks better now, but i still have a color managment problem:

http://www.youtube.com/watch?v=Tbhb61oUAX4

[TheNeverman]

Do you have an exposure node attached to your rendercam?

[InfernalDarkness]

I think it's more of an issue with your texture map itself, actually. Note that it has many highlights already. I know it's not easy to find or make textures without highlights, as we often need a camera flash "in the field", but perhaps a nice clean scan or lighting setup without a flash would produce a better texture map?

Trick is to not get any speculars in your photo-textures. I think what's happening is the raytraced specularity (reflections) are screening against the photo's specularity, and thus producing the blown-out areas you're seeing, as well as blowing out the dark areas into the pixelly-mess you displayed in your video.

Perhaps save a test scene version of your scene, and try it with these basil leaves I made last summer, just as a test?

Diffuse:
http://img40.imageshack.us/img40/8984/basiltopdiffuse.jpg

Bump:
http://img828.imageshack.us/img828/6598/basilbump.jpg

Alpha:
http://img706.imageshack.us/img706/8177/basilalpha.jpg

There's still some specular in the diffuse channel, but not nearly as much as we're seeing in your banana leaf texture. No actual "whites". And I don't think this is a perfect or "great" texture example (my basils) either, just a test to see if it helps?

[ColonelMillerSG21]

Thanks InfernalDarkness, that was very helpfull :)

That´s the actual status (still some problems):

http://www.youtube.com/watch?v=JwLQ9PM3lH0

These are two of my new maps:

http://img824.imageshack.us/img824/3189/miniblattbump.jpg
http://img708.imageshack.us/img708/6264/miniblattcolor.jpg

[InfernalDarkness]

Regarding your color map there, is that the file you're using for the diffuse channel? If so, be sure to overpaint the colors beyond your alpha (cutout opacity) map. You can kinda see the white edges somewhat in your renders, due to the image node filtering process.

Are you using mipmap with a filter strength of .2 already, for your diffuse node?

[ColonelMillerSG21]

Not the final version. When i´m using vue, i always give it a green background, in a smiliar green. I wanna do it the same in Maya.

Are you using mipmap with a filter strength of .2 already, for your diffuse node? No, why? (I´m using the standard filter)

[InfernalDarkness]

Then that would be the quadratic filtering at a strength of 1? Sometimes this can wash out your details a bit too much, and it certainly reduces clarity. Your maps look really good and perhaps a lighter filter would bring out more detail in the renders. I generally end up with a mipmap between .1 and .5, depending on the texture I'm working with, but of course feel free to play with it and do whatever looks best!

[Ekenryd]

Just a note: I notice your cutout map has anti aliased edges. I did a test in vray some time ago, one render where the leaf alpha had AA-edges like yours and one where it was only black and white, no shades of grey/AA. Render times were 0.50 and 2.55 respectivily. I don't know if it works the same in MR, but just in case you should probably get rid of the AA to get render times down quite a bit. You wont notice the loss of AA when rendering.

[ColonelMillerSG21]

Much better, thank you so much guys :)

That's how it looks now: http://www.youtube.com/watch?v=_-rLp8W9OJs (1080p)

I´m still workin on the specular and the translucency.

[ColonelMillerSG21]

Hey,

I made a displacement map to get more details and to improve the highlights, but still problems and more problems. I think the last problem is a lighting problem. I made a small video to show it to you:

http://www.youtube.com/watch?v=Qn5Ef_oIlE4

[InfernalDarkness]

You're using the mia_material_x for this leaf, correct?

By default, the mia_mat_x has enabled "fake specularity" which is similar to the Blinn and Phong in how it renders. Specularity itself does not exist as an actual visual effect; it's simply a function of the reflections of light across a surface and the angle of incidence and also the wetness of the "camera" (your eye). Thus, "fake specularity" where the shader tries to mimic this effect based on the direction of light hitting the geometry and the angle of the camera in relation... But this is not a "physically correct" method, just an approximation.

In the Advanced rollout for the mia_mat_x, there's an attribute called "Specular Balance". Default is 1 (fake specular) and 0 is "reflectional specular only" basically. At 0, you need physical lights in the scene to make it work, but you should be using physical lights anyway with mental ray. The sun/sky will work, for example, but not a Maya-native directional light unless a mental ray light shader is attached.

Play with the Specular Balance a bit and see if that helps?

[ColonelMillerSG21]

Yes i´m using the mia_X material. The Specular Balance didn´t work very well:

http://www.youtube.com/watch?v=sXUzkcgj4SI

[InfernalDarkness]

To be honest, I think your leaves look fine. Depending on the final image/animation, you can probably just handle the rest in postwork with Photoshop or your animation compositing application. Without a scene to judge their realism from, it's hard to say what else you could do.

One thing I was curious about, why is it black in the viewport? I tend to like having my viewport show my textures, so I can at least get an idea how it'll look before rendering. And you can quickly check your "fake specularity" by pushing 7 as well (render viewport lights).

[ColonelMillerSG21]

Thanks ;) Well, i don´t think that i can fake the specular highlights in Photoshop, but you are right.
To the viewport: Most of the time it´s turned on, i swear ;) I had a little perfomance problem because i was rendering with another program in the background.

This whole Plant thing is for a videotutorial on my tutorial channel. That´s the reason why i wanna make it perfect.

[ColonelMillerSG21]

I finished the leaf. I will render it with multipass.
But before i render it, i want to add some waterdrops. I created some spheres with a mia material and refraction turned on, but the water is black when i take it on the leaf(It works on all other polygonal objects):

http://www.youtube.com/watch?v=CT1bF-Nw--0&feature=youtu.be

Edit: Problem solved