Hello all. I am currently working on a project where I feel that I am close to the solution, just trying to figure out how to put it all together.

The basic premise is that in the environment that I'm creating, the ground is supposed to change from a 'hot' color to a 'cold' color as these magical flowers die. The 'cold' spots spread radially outwards and then stop once they get x distance away from the origin.

So my main needs are:
- Smooth transition from the hot to cold
- Radial spread
- Control where each spot starts
- Color and texture change

What I'm thinking is a ramp shader with two extremes; hot(0) and cold(1). Then to script in an expression that says when a point on the geometry is given a value of false for the variable isitHot, go to 1 and spread outward for let's say 3 units. The variable isitHot will be manually changed with a set driven key(?) for direct control in the animation.

Or, if I am able to know the exact coordinates and frames when each of these flowers are dying, could I say at frame 233, coordinate xy becomes false for the variable? And then it can spread outward 3 units.

I'm currently messing around with the ramp shader and the sampler info utility since the ramp shader only has those 4 or 5 settings. Or can the shader be scripted directly and not go through any other utilities? I feel like it should, especially if there's only two textures. Or am I barking up the completely wrong tree, and just have two separate textures and use the script to tell maya which ones to use on the geometry as the animation plays?

Any help or tips will be much appreciated.
~Stardust