Animated bezier circle as mask + alpha ? Cycles burning plane

Support Animation and Rigging
1

Hello guys,

There is a simple plane and animated bezier circle having shape as mask. Animation similar to this:

The problem is that the plane has same transparent areas where i don’t want to mask appear. Any idea how to make it happen ?

According to mentioned video let we imagine that we want only to “burn” the word the rest will be invisible alpha. I tried also holdout in Cycles but then everything behind holdout is invisible too :frowning:

I will appreciate any reference to some tutorial or cycles setup how to mix shape mask + alpha, or some ray visibility trick having second plane as boolean operator.

2

Hey, i am trying to do something similar. I want a growing circuit on a circuit board. Same problem so to say. I want to animate the alpha mask. I tired to take the alpha mask substract it from a white image and animate the white images uv coordinates. I tried holdout, i tried so many things… in Unity i would just take a shader, mix alpha with a mask done. But in Blender… and I can not get any help on stackexchange