Seeking assistance to make a dissolve effect based on position using shader forge

Hi !
I’m currently working on a series of zelda effects recreation and the next effect I’m trying to do is this one.
Teleportation effect Twilight Princess
I’m pretty new with shaders. I learned the process to get a dissolve effect on a mesh but I can’t find the way to make the dissolve effect from top to bottom, mine is currently all over the mesh with a noise mask. So I’m looking for someone that could explain to me the process to make a mask that goes from top to bottom based on position (I think it’s the solution to my problem).
Thanks for taking the time to read !

Hi Rythmico,

I used this in the past, it’s Amplify Shader but both are very similar so you should’nt have that much problem finding alternative nodes,

Also it could be improved because it’s based of world position (couldn’t find any way at the time) but by offseting the mesh position with a script it’s working just fine (Min Y Pos, and Max Y Pos on my side)

and this is what you get :