mia_material for realistic leaves

#121

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. :slight_smile:

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. ITā€™s slowwwwwwwwwwwwwwwā€¦
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.

#122

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.

#123

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.

#124

royterr ye i know about this.

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

#125

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 - itā€™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 weā€™ve been discussing here. Iā€™ll post a pair of renders tonight that illustrate this point, when I get back home.

#126

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 ā€œstandardā€ sphere particles, scaled in Y axe).
Tell me what do you think =)

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#127

Iā€™ve been following the thread for a while trying to achieve a result such as Alessandroā€™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 Alessandroā€™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

Original Rendered Raw Image

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Adjusted & Gamma Corrected Image

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Composited tree in Allessandroā€™s original Image

#128

I think your leaves look fine, from a rendering standpoint. From a modeling perspective though, they arenā€™t sky-sensitive, and most plants surely are.

Postwork and composition is the other 50% of the battle. Iā€™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 itā€™s way faster to control things in post than it is to re-render constantly, too!

#129

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 Mayaā€™s CM settings properly. It can be a confusing subject, but itā€™s a very important one and is fundamental to creating a photorealistic image.

#130

ditto
also looks like you have an issue with your alpha mask on the leavesā€¦

#131

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 bordersā€¦ It even was there when I offset the alpha map in photoshop a couple of pixels to the inside.

#132

I tend to set the filter on the cutout opacity texture to ā€œnoneā€ instead of mipmap or quadraticā€¦ looks sharp and correct if the alpha is good.

#133

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

#134

Hey moz, remember doing that but i am sure that didnā€™t fix the problem. will have to dig up a scene where we had the problemā€¦

#135

isnā€™t it just a premultiply issue in your case? Did you turn it off?

#136

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?

#137

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.

#138

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

#139

For the sake of reference, here is the texturing method used by the master (Tastao_wayne) from the Forests for mental ray thread, specifically this post.

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.

#140

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