PDA

View Full Version : radiosity and uv map.


limkinkwan
07-20-2003, 05:22 PM
hi,
I'm doing a 3d animation recently, as I hope to get realistic lightning result, I choose to fake radiosity in LW, so we should do the uv map 1st right..,

The problem is my scene has a lot of object, how can I do the uv map together in modeler? let say, if got 200 object inside a scene, how to do the uv map together then fake it ? if I do the setting( like where to put the tree,house...grass,everything) in modeler and do the uv map for it, I found that is quite heavy to move the object in modeler....

so should I do all the setting in modeler 1st and then uv map for it or has any others good idea ? :applause:

CG.p
07-20-2003, 07:06 PM
Usually when someone fakes radiosity they dont' need a uv map. Are you taking about baking it? The only other erason why you would need a uv map for radiosity is if you were going to pain a fake radiosity solution. I have never heard of anyone doing this but it isn't impossible.

If you want to fake it, check out EKI's plugin pack with overcaster.

http://www.kolumbus.fi/erkki.halkka/plugpak/



Now for any uv maps. That is really something that you sound be doing on each object, usually when you are modeling the object.

Give us more details so we can better help.

-CG

Finkster
07-20-2003, 08:15 PM
I'm no experty on radiosity baking, but if that is what you are intending to do - with surface baker, be careful...it is only suitable for certain kinds of animation. The surface baker bakes the radiosity effect on top of each objects texture, so you should have your UVs made and textures painted before hand.
Be careful though, because after surface baking you should have each object's surface luminosity at 100% and diffuse at 0% (all surface colour data has already been calculated).
This means that if any of your baked objects are moving in the scene, their shadows will not move with them, because the shadow has already been baked onto the surfaces. You can overcome this by doing multipass rendering and compositing, but it may get a bit complicated. I think radiosity(surface) baking is best for fly-by type animations, where the camera is the only moving object.
You could use EKI's overcaster, but as far as I know, it only fakes global illumination effects, such as a skylight, rather than radiosity from light bounces.
I think your best bet may be to light the scene manually, by placing bounce lights, with soft shadows (spotlights or area lights), in areas of the scene where light will be bouncing off surfaces and producing secondary illumination. This option gives you the most control (intensity, falloff, quality etc) without the nasty render time of real radiosity.
Of course if you just want a nice global illumination, skylight effect, then overcaster is a safe bet and is of course indepedant of object UVs.
It really depends what type of effect you are trying to achieve.
Give us some details, maybe we can help more.

limkinkwan
07-21-2003, 10:28 AM
yes thanks for your suggestion...
actually I'm doing an animation is about 2 ape walking in the natural environment (lots of tree, stone, grass,etc..) then take a durian from a durian tree and eat the durian..., but there have some concept on it, the environment will not be animate, just the ape have some animation.

No map need? ohh..I just realise there got 2 option in the "Surface Baker" option - "Bake to object" or "Bake to image". before that I follow the tutorial is "bake to image", so just now I try bake to object, so no need uv map anymore. so If I got 200 object, that means I need set the surface baker setting for each object in 1 surface?//

em...can I just bake the environment, but the 2 ape(orang utan) animation I add it in later on by using some light on it?:)

Finkster
07-22-2003, 03:32 AM
I suggest you just do some testing to see how well the radiosity baking will work with your animation. Try a simple test animation of the ape interacting with the durian as that is most likely where your problems will occur. Play around with the settings until you get a good result. If it doesn't work out you could do a seprate shadow pass for those elements that are moving, then composite the shadows with the rest of the animation.
Also, won't you have UV mapping anyway, for texture mapping your objects? Or are you using all procedural textures?

limkinkwan
07-22-2003, 05:25 AM
erm,, I'm using image map and procedural and a bit uv map on my object. I will try it on, thankx a lot Finkster
:)

CGTalk Moderation
01-15-2006, 04:00 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.