As you can see, the new face normals are all identical to the original one. I wonder if they could have been smoothed in some way?
None of these will auto-fix it (this is just one triangle, I have a whole mesh to fix).
- normals / recalculate inside
- normals / recalculate outside
- faces / recalculate normals
- faces / shade smooth or flat (just to be sure...)
- smooth vertex weights (just to be sure...)
- smooth vertex (just to be sure...)
beautify faces (just to be sure...)
It looks like that after a subdivide it will auto call normals/recalculateInside once, because I tested recalculateInside on some non-subdivided faces and the effect was similar.
So I wonder if it could subdivide using other kind of normals recalculation that would not break it that much?
Or a way to recalculate normals properly after subdividing?
A not so good workaround I found is:
The mesh has something called "Custom split normals layer".
So I went in mesh edit mode, now at the "Properties" window, at the "Data" tab, click on "Clear custom split normals data".
The moment I did that, the way the whole mesh looks changed somewhat, I could say it became more simple, like more basic or less impressive, but the overall looks didn't look bad at all, just simpler.
Subdividing now won't completely mess the looks, will just subdivide it quite well, but with that normals layer lost already...
I still wonder if it is possible to subdivide keeping the "Custom split normals layer" w/o messing it?
Using blender 2.79