Vertex blending and alpha maps for game terrain

MisterSnips

Hi folks

I'm trying to paint terrain in max for export to a game engine using vertex paint and all 3 rgb channels to have separate textures. Ive seen posts on people explaining the theory (e.g. http://www.polycount.com/forum/showthread.php?p=729964) but I cant for the life of me get it working.

Does anyone know of a good tutorial?

Also, is it possible to add decals in the same material (I know, he wants the moon on a stick I hear you cry! ;0)

Hope someone can help
Cheers!

Ace-Angel

3DS Max is a bitch when it comes to Vertex Painting and for them to work correctly, here is an example of a tutorial on what I mean:

http://www.cgshelf.com/vertex_paint.php

Never got it to work myself. I would suggest real-time shaders instead if it's an option, and alot of it depends on what game engine your exporting to. If it's UDK, then you can simply create the material in there, and call it a day.

[ame]http://www.youtube.com/watch?v=LI4ZHVDuiKo[/ame]
http://www.chrisalbeluhn.com/UDK_Advanced_Vertex_Painting.html

Mik2121

Yeah, as Ace-Angel said, you might want to see if you can do vertex painting within the engine you're using. If it's UDK, doing vertex painting from there is a much better and faster process.

elec²ron

To get a real time preview of the vertex blending in max i'd say your best bet is shaderfx. http://www.lumonix.biz/shaderfx.html
There is a tut on texture blending at the bottom of that page.

One of the problems with max's vertex paint is you cant work on the seperate rgb channels like you can in photoshop, I would suggest stacking up 3 vertexpaint modifiers and paint each colour on a different modifier.

rasmus

But remember to use the "Add" blendmode or they will overwrite eachother :P

leechdemon

rasmus wrote: »

But remember to use the "Add" blendmode or they will overwrite eachother :P

Add is totally the way to go. The results look like hell, but as numeric values they work correctly (AFAIK...).

The layer system is a bit confusing, but I've found that if you colapse the stack every once in awhile, it helps things. You may want to name your modifiers too; either "Vertex Paint - Red/Green/Blue" or whatever material each one corresponds to.

MisterSnips

Cool, thanks guys, I think I've got it sussed in Max now but I'll give that shader a go, looks good. Cheers

Ace-Angel

Yep, I use ShaderFX alot, the only way I can even stand 'showing' anything else in Max in this day and age.

Anyhow, if you're still on the road to get Max to show shaders (especially vertex blending), I have a vertex shader lying around. It's pretty bare bones (only the diffuse has been created) but it essentially have everything from Cavity masking to individual channels RGB mapping (as well second UV option for enabling world offset textures).

http://www.mediafire.com/?64ph42mv6t88a4y

It's in SFX format (ShaderFX) and it's pretty big, but don't worry, if you know the basics of materials, you will be able to get your head around it.