Strange surface normals, how do I recalculate?

Support Modeling
#1

I converted a model to *.obj and imported in blender, but the surface normals are all weird.

  • Recalculating or flipping normals does not work.
  • Looking at the “vertex-per-face” normals I see that the normals seem aligned parallel with the surface!
  • One thing I’ve had succes with is sculpting the object with retopology on and zero strength. This fixes the normals, but the topology is messed up.
  • Setting vertex normals from faces makes the mesh look like smooth shading is turned on. Toggling between smooth and sharp returns (more or less) to the initial problem.

strange_mesh.JPG285×527 21.1 KB

vertex_per_face_normals.JPG387×718 80.4 KB

Attaching an example in case anyone want to have a look themselves.
strange_mesh.blend (522 KB)

#2

Very odd, I am not sure. Sorry that’s not helpful, but I tried :slight_smile:

#3

ex.JPG994×887 57.9 KB

Not totally sure what the command does, but when unchecked (it is checked in your file) the problem seems to go away.

1 Like
#4

Wow, totally took care of it. I’ve never heard of ‘auto smooth’ before, but I must have turned it on by mistake.
Thank you very much! Blendering went from frustrating to fun again :smiley:

#5

Sure thing. I’ve never heard of or used it intentionally before either. I think the majority of what I know how to do in Blender started with just clicking random stuff anyways!

Enjoy!