"Pulling" an animated material through an object

[Jonathan]

Im trying to figure out how to pull a material through an object as animation. For example, how might a bare stone wall gradually become a painted stone wall as if being literally painted onto the surface?

[Flint]

You could animate a blend material which would fade from one to the other. If you wanted it to look like it was being painted in strips maybe an animated mask would work, but not tried this myself.

[Bruce Hart]

You could use a blend material perhaps, with an animated mask map. Depending on what you are doing you may need seperate UVW mapping channels for each map. Your mix mask might be a gradient or animated noise of some kind. If this mask has a different mapping channel from the first two diffuse materials you could animate the UVW mapping gizmo to "reveal" the transition between the first two colours.

 

Edit: sorry replied the same time as Flint above

Edited September 24, 2011 by Bruce Hart

[Scott Schroeder]

Do it in post. Render the bare wall and the brick wall separately. Then in say, After Effects, there is a already built layer transition that mimics something being painted on. Or you can create your own mask in AE just as easily.

 

Post will save you on re-rendering headaches and gives instant feedback. You don't always have to do stuff like this in Max or as a baked in render.