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Shadows through transparent maps, 3DS Max 08
Charcoal 
19/11/07 12:26:39 PM
Hero
Immortal


So, I'm making a level for Ut2k4, and I'm wanting to bake the really nice 3DS max shadows to a texture.

Unforutnaly some of my textures have transparent areas, and any combinations of renderers and lights I've tried don't allow the light to penetrate through the fully opaque bits.

Can anyone give me some ideas?

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Site: http://www.charcoalstyles.com/
Blog: http://virb.com/charcoal

Stop squirming and die like an adult, or I'm going to delete your backup.

peedub 
19/11/07 4:48:46 PM
Overlord

Well first of all light isn't suppose to penetrate through fully opaque surfaces as it's 0% transparent :)

So you're baking a texture and shadows are appearing on the transparent surfaces where you don't want them to?

I'm not experienced in baking but I know that you've got to use ray-traced shadows on lights for shadows to pass through transparent surfaces - shadow maps don't do they trick.

Secondly, if you just bake the texture then use the transparent map as a mask you may be able to Photoshop the texture how you want it. Sorry, that's just a suggestion I'm throwing out there in case it helps - I'm not exactly sure on your situation so I don't have anything better to suggest :)

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Charcoal 
19/11/07 5:44:39 PM
Hero
Immortal


Oops, I meant the other way around, %100 transparent :P

To explain it a bit better:

I have a piece of land and (right now) a tree on it. The tree has a trunk and tome single poly leafs, with a texture on it that has transparency (single png file, will making a separate opacity map help?). I want the light (that I have as an "Adv. Ray cast" right now) to "shine through" the transparent bits of the texture, leaving the shadow of the leaves on the ground.

I'm fairly sure it's doable (but will take a long time to render), but I need to know how, as it's not working right noe.

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Site: http://www.charcoalstyles.com/
Blog: http://virb.com/charcoal

Stop squirming and die like an adult, or I'm going to delete your backup.

peedub 
19/11/07 6:17:57 PM
Overlord

If you've currently got transparency in the png colour texture itself then I think this would be why the alpha shadows aren't working correctly. Usually you have the colour texture as one map, and then the transparency/alpha mask as another map, so give that a try.

It shouldn't be too hard to create the alpha map from the colour texture that you already have - try desaturating the texture and see if that gives a good-enough effect.

If saving the alpha texture as a png with transparecy doesn't work, try a tga. And when using the alpha texture, the colour texture doesn't need transparency, so it will only need to be a bmp or png without transparency.

By the way, are you using the tree shadow texture as a decal/overlay, or a tiled texture applied to a certain "brush" or block?

edit; added some stuff, subtracted some stuff.


Edited by peedub: 19/11/2007 06:20:58 PM

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Charcoal 
19/11/07 8:33:24 PM
Hero
Immortal


Tried the two separate maps, full colour bmp for the diffuse, greyscale bmp for the opacity. It didn't work either.

I'll be using the rendered shadow map to darken the right parts of the final diffuse texture.

-----
Site: http://www.charcoalstyles.com/
Blog: http://virb.com/charcoal

Stop squirming and die like an adult, or I'm going to delete your backup.

peedub 
19/11/07 9:00:05 PM
Overlord

Hmm, I'm not sure what wrong with it then. Looks for something like "transparent shadows" in your lighting source and see if ticking that makes a difference.

Otherwise, break it down. Set up a new test scene with test maps to see if you can get it working in a simpler environment.

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Charcoal 
19/11/07 9:10:06 PM
Hero
Immortal


Got it!

It was part of the light, in a rollout called "Optimizations", just under the Adv. Raytraced rollout.

Thanks for the help, peedub !

-----
Site: http://www.charcoalstyles.com/
Blog: http://virb.com/charcoal

Stop squirming and die like an adult, or I'm going to delete your backup.

peedub 
19/11/07 9:37:10 PM
Overlord

Ahhh good to hear.

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