I need help masking a snake

[Wolfo]

I want to simulate a Snake escaping from a leg unrolling with a mask, but I don't know how to archieve that effect, the explanation is better with an image what happens and what I do.



Heres another sample of other failed solution I tried.

[Víctor Paredes]

The masking layer must be always on the bottom of the group. In this case, the vector layer must be on the bottom and masking. Something like this:

Group (Hide all)
- Image (Mask this layer)
- Vector (Add to mask)

[funksmaname]

also, don't forget to render frame previous... in some cases of masking the canvas doesn't correctly represent the rendered output (though it should on a simple set up like this)

[Wolfo]

Thank you very much, I made it!!

[Víctor Paredes]

I'm happy to help. Clever idea with the snake, by the way.