Material Mask animation

Hi everyone, I’ve been looking/asking this question for way too long, but i’m kinda surprised how there is not a lot of documentation regarding my problem online (or maybe I don’t know how to search)

Anyway I have a paper model that I created with Maya and textured with substance painter, i’d like to create an effect where a drawing appears on the paper (to simulate someone writing it) or at the very least have it fade in from bottom to top or vice versa.

Here’s a screenshot : I have my scroll mesh, and I put a decal (i dont want it to be a decal, and it doesn’t have to have a background, just the drawing part) with a similar texture of what I’d like to appear Imgur: The magic of the Internet (its not supposed to have a cross, I just used a random master material of a decal)

How to go about this ? I have tried a couple of things:

-Have a material with two ‘makeMaterialAttributes’, one with the original paper texture, and another one with the same paper texture, but with the drawing on it → put both of them through a BlendMaterialAttributes and have the alpha be the drawing part in black on white background.

Results: the BlendMaterialAttributes gives me an error about float3 → float and I don’t know how to fix it. Here’s a screenshot of it : Imgur: The magic of the Internet
The lerp at the top that goes through the left of my screen is a material function of the paper being burned.

-Have my original material and put it through a lerp, have the alpha be the same as the one above, the a my paper material and b a noise texture but it doesn’t work as well.

I’m obviously confused and doing something wrong, what could i do ? I feel totally lost, most of the tutorial I was able to find was to blend between two texture through an alpha mask, but it’s not exactly what I want to do.
Ideally I’d like something like this: Writing Text with Bleeding Ink (Wisp / After Effects Tutorial) - YouTube but even just the animated writing would be enough. Thanks

It fixed it ! Thanks. I feel stupid now it was that easy. Is there something I could add to the mask to have it appear as a gradient from bottom to top ?

Have you tried taking the alpha mask from the alpha?

336276-screenshot-1.jpg

Yes, you could use a linear gradient. I don’t know how convincing it would look.