Hi
I am trying to create a mask that allows me to go from one texture to the other in translation… What I mean is not by blending like Lerp is doing
I have a texture of the face of my character with no damage, and another face of my character with blood dripping. I would like the mask to create the effect of the blood slowly dripping on the face.
Any idea on how to achieve this result?
Thanks 
Assuming your UVs are aligned with the top of the head at V=1, you could always animate a value to compare against the current V position, and discard pixels outside that range.