How to get smooth shading?

Question

Using XTK, I tried to load an STL file. The shading is NOT smooth. What all modifications I need to do to get smooth shading?

Answer 1

XTK doesn't re-calculate the normals (yet). Since the .STL only has face normals and no vertex normals, it won't be smooth

you can convert the model to a .vtk file which supports vertex normals.

also, you are welcome to contribute the normals calculation code :) for freesurfer meshes, the normals get recalculated so all the pieces should be there