Ok so,
I'm in need of a shader that applies orientation to the leaves so that they keep on facing the camera. Just like sprites.

I wanna have a tree composed by 2 separate meshes, trunk and leaves, but it would be a pain to singularly place sprites while generating them with a 3dsmax plugin is much easier.

Can it be done? I'm not a programmer.

Ciao Pietro... Se mi scrivi in italiano cosa cerchi ti posso aiutare...

@DavideG: I dont speak italian, you give already a solution? Please write in english...

no he didn't, can you please help?

if you upload the model in MDL format I´ll take a look at it

As a programmer (and a poor modeller), I think the sprite way is the best...

All you gotta do is attach the sprites to specific vertices of your model,
and then they'll always be positioned correct, and always face the camera...

That is a very bad proposal EvilSOB, as the sprite aproach will be many many times slower while it will be fast with a shader.

I can't explain it easier

Ok you have a mesh composed of 20 triangles (10 quads). Have them face the camera all the time.

Can you do that in a shader? can you script that for me please? I don't think it's that difficult from a theorical point of view but like i said i'm not a programmer.

In a vertex shader, each vertex is generally only aware of its own position and its normal. There's a bit more than that, but basically you want each quad to rotate around the quad's centre, and in order to do that each vertex needs to know its position relative to its quad's centre, and this cannot be done in a shader.

I would personally do it with bones, if you're using the A8 beta, and do bones animation in the vertex shader. Use ent_bonerotate to orientate the bones when you need to. It'd be worth a try, anyway. It might still be slow with lots of bones, and it'd be tedious to set up. It could be done in A7, but all the vertices will be moved using the CPU, and that'll be slower.

Alternatively, if your Max plugin can put down single vertices instead of quads it wouldn't be much effort to write a function that just places a sprite at each of those vertices -- like Slin said, this'll be relatively slow, but A8 has sprite instancing, which might make up for it.

In short, I don't think what you want to do is feasible in A7, but A8 might have what you need on the off chance that you're a private beta tester.

Jibb

I see.. this explains a lot. Now I see why loopix trees are done that way, static.