Is there a plugin that does this?

[EricChadwick]

I assume you;re talking about procedurals in a 3d program, not Photoshop?

The method totally depends on which 3d software...

[mankor]

you would need somthing like body paint from maxon or deep paint from right hemisphere..other than that youll have to learn better unwrapping techniques..or you could select the polys around the lips and use the multy-subobject meterial (if your using max)..let us know what 3d app your using

[Stroker]

I was recently playing around with mapping channels for lips.

UV map the model for the majority of the textures in channel 1.
Then UV map the model again, but with the lip area insanely big in channel 2.
Then just paint a mask to blend the two.

With the lips in a seperate channel, and being bigger, I can paint as sloppy as I want and still get decent results. Or even use another set of procedurals.

I'm a Max user, BTW. No idea how mapping channels translates to other programs.

[Mauritius]

but is there any way to paint directly on to the model

There is. It is called "vertex variables". Basically you attach a variable to all vertices of the model. This can be a color or simple a percentage value. This is particularly cool with procedurals, as it lets you guide any parameter of the texture locally through these variables w/o the need to ever create uvs. The downside is that your control is limited in resolution to that of your model's geometry. But for many applications, especially today where models tend to be highly complex and dense, this can be a very viable approach.

One thing that many programs unfortunately don't offer is a non uniform scaling of a procedural pattern.

Imagine some procedural scales on a dragon.
Not only should they stay the same size each (as they are made of some ridgid material), but they should also vary in size, depending on where they are on the dragon. While the first requirement must be taken care of programmatically in the shader generating the pattern, the second one is easy to archieve by painting a grayscale percentage scaling pattern on the vertices of your model.
A real world example of such a technique is e.g. found in the movie "Reign of Fire".

.mm

[EricChadwick]

That's really interesting. Do you work with an app that supports this?

Brings to mind all sorts of ideas I could apply this methodology to.

[Mauritius]

Well, in Maya this is possible if you use a RenderMan compliant renderer (not necessarily PRMan) through Pixar's MTOR or the free open source Liquid plug-in, (which e.g. got used for Lord of the Rings).

All RenderMan compliant renderers support vertex variables naturally since this has been part of the spec since its inital release in 1989 (!) ...

An ideal combination if you do "real world" stuff (aka you earn money from it) and already own a Maya license is to download Liquid and run it with the yet free 3Delight renderer.

Ahh, and some addition: if you are into procedurals but don't want to tackle RenderMan shader writing, you can use DarkTrees through a free DSO available on the DarkSim site -- works with all RMan compliant renderers avialable these days (seven, to be precise).

.mm

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