In this model I tried to apply subdivision to create a smoother topology for 3D print, but in the back something happens and even when I put the mean crease to 1, it doesn’t do a lot for the back (front looks a bit better). Also the front flat parts (ngon) I would like to smoothen/subdivide for 3D print, but doesn’t seem to work so far with the options I tried Subdivide, grid fill (no equal vertexes) or triangulate faces (weird shapes). Any suggestions?
Also my model appears black when I want to sculpt and on the internet people say this could be a face invert problem, but the alt M option doesn’t seem to work. Any ideas what caused this and how to solve it?
The topology of your model is pretty messy on places, with multiple unnecessary triangles. Subsurf won’t handle it well. Lucky for you, subsurf isn’t necessary as this mesh is already round and dense without it.
You can put a bevel on the flat parts ro sharpen the edge (select all edges around the flat spcem ctrl+B). That is, if the below is what you’re aiming for.
what do you mean by “in the back something happens”? The topology is not very nice but I’m not sure there’s any problem, there are no flipped normals, maybe join some vertices to make sure that there are no overlapping faces:
