Processing Forum

I'm trying to apply a displacement on the outer side of a tube, or to a custom mesh (imported .obj)

how to approach that?

I've seen this examples:

But I don't know how to chance the Z to the Normal

I guess is something like the SoundVase https://forum.processing.org/topic/sound-vase

but unfortunately I can't understand how that is done.

is there a simple way to achieve a image displacement on a non-flat mesh?

Thanks