Object that pushes vertices away

Hey guys, this is my first post on the forum. I‘m not a native English speaker, so please excuse my language… I‘ll try do my best. :slight_smile:

I need a little help!

In the last view month I was working with blender on a little star wars short film (A shuttle landing on a lava planet with some mountains…). The film is actually finished and on youtube.

I‘m relatively happy with it, but when I look at it again, the lava sucks… :slight_smile:
So I want to do that part again.

The lava texture looks fine, but it should float around the mountains, instead of floating beneath them.
The lava is made with a procedural texture on a plane. So what I did was pushing the vertices of the plane on the x and y axis away from the mountains. (By hand with the proportional editing tool.) That was working but not all to well. :slight_smile:

What I‘m now looking for is a way to do this automatically.
In a way I need something exactly like the cast modifier (see image) but with a more complex cast types. (in my case the mountains…)

Maybe someone can give me a clue!