Exterior Rendering : Mental Ray or VRay

[Cypher666]

It's not as much the lighting as it is the materials, try adding some specular highlights and reflections as well as some subtle bump maps. I don't think that you really need photons for this scene, try it with only final gather enabled as it should bring your render time down somewhat. If you wanted to go for ultimate realism you could use some physics shaders like DGS, there is plenty of info about these sorts of shaders scattered around these forums but in particular the mental ray shader forum has loads of info.... if you have the time to read it:thumbsup:.

[gxsaurav]

i have compleated my reading about DGS, but the thing is, a reflecting material is good, only if it is reflecting something, as u can see in this scene, there is nothing to reflect, in front of the house

also, the above "model" Render is done using a skylight, & FG value of 100 only...that did gave me nice GI shadow, however, low ammount of light as u can see

For the walls, i have used architectural materials, with a custom made, diffuse map, with UVW mapping applied at the home, as it is made using one box only, i also placed the same maop in the bump map slot, previously it was a lot (600), so i decresed it to 200 & now it seems a good bump value....DGS will be good, but will take a lot of time to render, but, i will render one scene for trial with DGS, it might work thanx for your reply

how do u guys do it, can u tell me your tricks

[MikeBracken]

If your using Mental Ray you can put an inverted sphere around your scene to keep the photons from bouncing off into eternity. And you can use the environment slot to get some
reflections on your glass. I agree that materials will help alot. Almost everything in real
life has some kind of specularity.
Good luck.

[gxsaurav]

what kind of inverted sphere, i tried to put a hemisphere with normal modifier & got an error that "Cannot store photon after emitting 10000 photons", can u show an example plz

I m gonna make a render with DGS materials, for the wood, & walls, stone

I have added speculear to the materials, don't know why it is not showing up in the render, maybe cos the red gate has nothing to reflect

[gxsaurav]

here is the current render, i m using DGS for the wood material & added a few things in the front to reflect

the gate is using a metal texture, but still don't know how it gets like that? U know, pinkish....now how to continue further

http://img83.imageshack.us/img83/1296/cam2f4us.jpg

[Cypher666]

Like MmikeE said, an image (hdri would be best) in the enviroment slot would really help coz then your objects will have alot more to reflect, even if you don't want an enviroment in the background for the final render you should have one there for now just to make it easier to see exactly whats going on with the reflections while your setting up materials. I can see the reflection on the wood but the gate is just reflecting the enviroment, which is empty, so it's just reflecting flat white and thus makes the red look bright pink. Don't go to crazy with the dgs shaders as they are slow to render, as long as you have a spotlight in the scene you can just use simple specular highlights for most surfaces that are glossy (like the walls etc). Sorry if my advice is a little confusing, I'm not that great at explaining things, but if you have any questions at all don't hesitate to ask. There are no stupid questions, only stupid answers.

[gxsaurav]

thanx Cyber66, i have a few HDR images which came bundled with 3D Max 8, i m gonna put them in Sky light map slot & enviroment slot, to see how the reflection is going......

I think i have been doing the light abit wrong in, i looked out side the windows & realised, that light comes from everywhere, not from a point source, so it's more like Fill light everywhere, gonna try with day light setup again, but the problem with that is that the shadows are hard

[gxsaurav]

as adviced, i put an HDR map in the skylight map slot, & changed the light setup a bit

as i said before, i found that light comes from all over, in this house, as this is a replica of my own house, now there is a tree in front of the house, which casta shadow on the house, which is very blurred & faint, so i m trying to get that look via Area shaodw, for this, I set up an mr area spot with area shadows on, i also put an IES Sun with ray traced shadows & one skylight, seems like the Pink gate problem is now solved...as due to the HDR it has something to reflect

I made a small render, low sample, how is it, seems like the green color cast is very strong, & some problems too, this is my current GI settings, for some reason, setting only the mr area spot isn's showing any photons at all, only with IES Sun, photons are being showing, here i need to ask, what photon size is good 20 or 100, it just makes the image more bright. How to solve that green flash problem, increse the FG value or add more photons, right now FG = 400

http://img231.imageshack.us/img231/7893/triallighties7if.jpg

here is the photon only render, Photon size = 100

http://img231.imageshack.us/img231/7691/15ig1.jpg

The GI setup

http://img231.imageshack.us/img231/1236/snag00004dp.jpg

[Cypher666]

Sorry, I didn't explain very well. What I meant to say is but an HDRI in the Background enviroment slot, not that of your skylight. It is fine to have it in the skylight aswell but you are still not getting proper reflections from the background. here is an example:
http://i72.photobucket.com/albums/i178/cypher666_2006/dgs_test.jpg
As you can see the first image is more like your current setup and the second image has a hdri in the background slot. Both are only lit with two MR spot lights, no GI, no finalgather.

Your image is alot darker with the new lighting setup which is why your gate looks red again, but I think the overall intensity is getting better (It was too bright before IMHO).
I think your photons look ok at 100, I assume 20 would be to low and you would get the "photon disco" effect, so I would leave it at 100. It would be a good idea to test the photon intensity of each light one at a time, making ajustments to the energy setting located in the "indirect illumination" rollout of you lights, just remember that skylights don't emit photons.

Your fg settings and amount of photons are good for now, but I think that green is coming from your skylight, I'd suggest getting rid of the hdri from your skylight for now and only have it in your background, it's better if you get your shaders and light intensity to look right first and then build from there.

Once again I'm sorry if this doesn't make sense:shrug:, but It's very difficult to explain some things. The way I learnt best was just to make a simple scene (a plane or a box with a teapot) and tinker with settings until I understood them properly.

[gxsaurav]

ok, i put an HDRI image in the enviroment slot of the image, gonna post the test render soon

There is a question i wanna ask, when i just add mr area spotloghts, there is no photon emission at all, it is shown in renders (photon flashlights) only if i use IES Sun or daylight etc...how to solve that....

I m keeping the FG count at 50 for trial render, it's fast, GI Photon size again to 100m

right now this is the light setup..one mr area spot in front, it is the key light, one mr area spot behind...for back light & daylight system for fill. Only the daylight system & key light are casting shadows

edit: here is the render, the light setup looks nice, this is infact how it is at my home...with an HDR map in enviroment slot

http://img133.imageshack.us/img133/5787/triallighties27zh.jpg

But i found that in IES Sun, there cannot be area lights, so all the shadows are very hard, this is my light setup

http://img133.imageshack.us/img133/586/snag00002fq.jpg One IES Sun as key light, one IES Sky & one mr area spot as back light, should i add another mr area spot for fill light?

for now i m gonna keep this light setup...gonna make a full render soon. how is it going now. I m scrapping the daylight setup etc now at all

[Cypher666]

Looking good:thumbsup:! Like I said in my previous post, you may need to isolate (disable all other lights) your mr area spotlights one at a time and adjust the energy in the indirect illumination rollout until you get the photons to show up (the one in the light parameters, not the one in the render dialog). I never use the IES sun (I heard it is a little slow) but sunlight shadows are usually very sharp on a bright day so I wouldn't worry about it to much, I quite like the crisp detail in the tree shadow. The reflection on the door is nice but needs to be turned down a little, can't wait to see it when it's done:bounce:!

[gxsaurav]

oh...sorry i previously mis-interpreted, on how to get the photon to show up, with the previous light setup i made this render, & don't know the reason for this strange yellow artifects, wrong photon value, or wrong FG Value (50)

http://img154.imageshack.us/img154/2417/artifects4lp.jpg

The map is a custom map I made in Genetica, yellow color, even if i tried making architectural material with yellow color & this map in bump map, i still got these artifacts

[Cypher666]

I have come across this problem before, however I can't remember how I fixed it ATM:banghead:. The answer is on these forums somewhere but I just had a quick look and I couldn't find it again:sad:. I'll keep searching and get back to you.

[Cypher666]

Still can't find that thread:cry:. I did do some tests however and I found bigger photons helped, so try increasing photon sampling radius to 150 or something like that.

[gxsaurav]

ok, gonna try that

so now i have 2 setups, 1 with IES Sun as the key light, which results in such hard shadows

& 2nd is the same thing, but with mr area spot as key light, which doesn' show photons when rendered, however gives similer shadows, but if the GI & FG are calculated somehow the hardness goes away. However in this scene, there is no artifacts problem

[gxsaurav]

With the mr area spot light setup, this the render i come up with, how is it, if the light setup looks good enough i will be working on the gate, wall materials now. I know, it's slightly not golden like sunny golden but exposure control was turned on,

http://img46.imageshack.us/img46/2631/cam2f5tt.jpg

i m posting my .max file here, take a look why the mr area spot is not showing any photons

http://rapidshare.de/files/23554105/Light_Setup_MR.zip.html

[Cypher666]

The reason your photons aren't showing is because your scene scale is wrong, your house is almost 15km long:eek:. Mental ray works with real world units which meant that I had to turn the photon energy WAY up before I could get them to show. The solution is to scale down your scene geometry and measure with the tape helper until it is a more realistic size (maybe about 50 meters long:shrug:), just be carefull because sometimes scaling your scene can cause other problems, I think you will be ok with this scene though.

[gxsaurav]

damn, i totaly forgot about the scale :banghead:

but if i fix it, that would mean, i will have to remodel everything :cry: or can i just use the "scale & minupulate tool" to scale it, or switch to "inches"

[Cypher666]

if i fix it, that would mean, i will have to remodel everything :cry:
Whoa thats a bit overkill, just try the scale tool, it should do the trick. If not just scale down the geometry (not the lights or camera) and then just move your camera and lights locally till there in the right spot again.

[gxsaurav]

ok, i m gonna do that. I m gonna make the whole Home 60 m long in left view as shown above, that should do i suppose

[gxsaurav]

i tried as said, for this, i looks with left view, & grouped everything, then set the resize to 5% of the original size, & placed everything again to 0 0 0

now, photons are showing, if the photon sanple size is .15 & energy is 8+ for each light....what should i look for now, i look at the 3ds Max bundled tutorial of GI & FG (the room with a light from top, some loft*_.max file), & they said, bigger photons leave artifects, but are fast to render, so what should i look for

1) Small size photons, which reach everywhere, & i will also increse the overall photon quantity, from 10000 to 200000, this will give me the Photon disco effect, & then use higher value of FG Like 800 or

2) Lareg size photons, large enough that they blend together.....& with FG value of 200, the results comes out nice, but there are a few artifects

what should i look for when setting the photon size

[Cypher666]

you want them big enough so that they blend together and look cloudy, but not so big that that they are smooth, it's really trial and error with this sort of thing. If you get artifacts you need to will need to increase your final gather samples but I wouldn't have them any higher than about 400, you might also want to play with your max/min radius as this will also help get rid of artifacts.

edit: they should be just a little bit bigger than what you had in this image:http://img231.imageshack.us/img231/7691/15ig1.jpg

[gxsaurav]

that image had the IES Sun setup with photon size = 100m. The only thing i disliked about it were that yellow artifects & hard shadows

[Cypher666]

yeah I realised that, I was just using it as an example of how big your photons should be, I should have said that in the first place:banghead:.

[JeffPatton]

You may want to simply use FG instead of FG & GI. Especially since you're using Max8 which has the FG bounce option. A typical FG exterior setting is pretty straight forward:
One skylight (blue color)
One mrSpotlight (yellow/orange color, depends on the time of day)
Turn on FG and set the FG Max. bounces to 2 or so (I wouldn't use more than 4 or 5)

That's it.

Here's a quickie lighting test using the simple method above:
http://jeffpatton.net/Gallery2/MR-morning.jpg

And I'd recommend that you currently do not use the exposure control. It will over saturate your colors. Instead, use a linear workflow IE gamma control. For more info on linear workflow with mental ray have a look here:
http://www.vizdepot.com/forums/showthread.php?t=3465

You may want to browse around that site if you're into the arch-vis work. LOT's of helpful info there.

[JeffPatton]

Oh good grief...Dang CGtalk backup issues made me duplicate posts.

[JeffPatton]

Woohoo, "triplicate" post...do I get an award or something for that?

PS - I'll notify a moderator about my extra posts here and ask if they will delete them.

[gxsaurav]

thats Jeff for giving your thoughts

I thought GI was required, i mean, an essential part of exteior lights, I will give FG a try, but what about the wrong scale problem....should i re-scale it using Scale tool, or just leave it like this, give an FG value of like 50 or 100 & render.

What about the other lights, i mean, there are 3 lights, one key light, which is shadow casting, one back & one fill, so...according to u, should i delete the fill & back light? & just keep the fill light & skylight

Since this is my project, of my Course, i had a deadline, tomorrow, i just rendered it with the current settings...but different camera views...it's not good, but good enough to be given as 3rd sem project, take a look at the composition i made in after effect here, the video quality is low to minimize the file size

http://rapidshare.de/files/23713407/Final_comp.avi.html

[gxsaurav]

as jeff said, i tried one FG only render with liner workflow, i changed the Gamma Value to 2.2, & rendered, this is how it is

one mr area spot, one skylight, FG = 50 bounce = 2, low sample, 5 mins to render.

Is it going correct, should i give decay in the key light? i m going to try another render with the fill & bounce light as well

http://img144.imageshack.us/img144/7350/lightsetupfg0xw.jpg

There are artifacts, which i suppose will be removed once I increse the FG value

[gxsaurav]

one more thing, jeff in your scene...the sky is blue color, how did u do that, is that some map in the neviroment slot or some other thing

[nwiz25]

:) heres a tutorial i made on exterior lighting in 3dsmax 8 using > mental ray 3.4 <

pretty long and detailed with lots of screenshots, hope you all like it ! :bounce:


http://www.cgtantra.com/forum/forum_posts.asp?TID=4739&PN=1&TPN=1 (http://www.cgtantra.com/forum/forum_posts.asp?TID=4739&PN=1&TPN=1)


cheers people!!:) :) :) :)

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