Always wanted to mix Materials in Cinema 4D with slider but had no idea to do that. Finally i come up with strange method... but it works :)
heres my steps:
1. create Cloner and set color of this Cloner to black
2. create and put two new Materials on Cloner. One for default color and other for second (additional)
3. create Effector for Cloner and set Color Mode On
4. in second Material check Alpha and use Mograph>Color Shader as Texture
now you can use Effector to blend Materials by playing with Falloff settings
maybe some of you will ask "why you need to do that whole thing? you could just apply one material and animate its parameters" but. just try duplicate it several times and then you will have to also duplicate materials and animate them separately.
cool thing is that second Material can also be Transparent and it will blend from non Transparent to Other smoothly.
you can also grab example file from here mix_mat.zip
cheers!
