Cycles, animate the color on part of an object

Question

Hello I am using Cycles trying to change the color of part of an object. Specifically in this case I am trying to change the color of part of a sphere from blue to green, while the rest of the sphere remains blue.

As you can see I selected part of the sphere and when I hover my mouse over the assign button and hit the I button for keyframe I get the error in the top of "Button doesn't appear to have any property information attached"

I heard that almost any value or button can be animated in Blender. So am I doing something wrong? Is there a work around for this? Is it possible to animate multiple materials on an object in blender?

Answer 1

You can't simply animate which part of an object has which material. Instead, you should animate the material itself and have different materials for the different parts of the object. In your case, you should have two materials. One material with the blue color for the part of the object that doesn't change color, and a material for the part that changes from blue to green.

You can animate the color by hovering the cursor over the color and pressing I.

Answer 2

Create a new material for the part that you want to change and assign it to the section of the mesh you want to affect.

(see : Add different materials to different parts of a mesh?)

Then the color change can be done in different ways.

Then over over the color of the material, add a keyframe. Change to a different frame, change the color and add another keyframe.

A different way would be to use an RGB mix node to contol the color of your object and animate the factor value:

Or Create two different shaders with the qualities you are after, add a mix shader node and animate the way they mix.