Hello. Another C4D-inspired post, from here.
To tackle this, a displacement shader can do an excellent job at render time, using standard geometry, that would otherwise require unreasonably high poly counts, if modeled.
The below image, rendered in Mantra, uses a curve (rather than a texture), to define the displacement area, and the shader can use a ramp to create the falloff.
Mantra might be slow, but the quality it produces is evident from the extremely clean displacement it generated. I'm not fully comfortable with Karma, but I believe I can reproduce a similar image with it.
If you inspect the attached scene, you'll see a bog-standard setup with the geometry. All the magic happens in the material shader, where you can query the distance between two objects (at render time), and then drive a displacement with that information.
Displacement Shader with XYZDist (Mantra).hiplc