Hey everyone!

I am trying to make a ~3mm indentation into both sides of my part. I tried using cut extrude with an offset from the surface, the problem is that there are multiple surfaces at work here. Knitting did't help, it says "the end face cannot terminate the extruded feature" when attempting the cut extrude.

Deleting the face makes the shape go crazy, so unusable.

I attached 2 pictures below, 1. the sides i want to indent and 2. an example of an earlier version, where I successfully did the same on the top.

So I want to create an indentation and then an extrusion which fills the gap again, but with a new solid. (all on a curved surface.

Please help!