Hey guys,
I believe DarthViper was correct when he suggested it was the high polygon density. I can shed some light on why that is the case.
Vertex normals are losing some precision when you import. The precision max error is around 1 degree or so. You if you can imagine, if you have a sphere more tesellated than that, some of the verts will have the same normals. When you have less tessellation, none of the verts get shared values, but then you get linear interpolation of normals across faces. That is what causes the ‘hammered metal’ look above. To fix that would require some fancy and expensive method of interpolating normals.
This became a big issue for some internal prototype project. They realized that UVs actually store with more precision than vertex normals. So for cases where you really need high quality vertex normals and hi poly meshes, you could consider an option like that.
Another way to fix this in your case would be to make that ‘sharpened’ side part of the knife as flat as possible. Right now you are trying to model a vert slight curve across that whole area, and such subtle curvature doesn’t hold up well. You could also try to just project flat normals onto those areas in the shade. You could use math to make the normals a bit rounded if you need that look.
@, thank you for the well explained response. Those points make a lot of sense. With that knowledge, we will go make some adjustments to see what happens. Thanks for your response!