Is it possible to make the polygons of a mesh smoother?
With the reflections, the polygons act like mirrors and are making these shapes…
I tried to convert to NURBS but it is still the same, then I thought I will increase the mesh number but I only found the button to decrease the mesh number.
you´re likely talking about the visible faceting, eg. on the blades. Sometimes meshes, eg. coming from the STL format come into Rhino facetted, which means there is no smothing between them. The _Weld command might help here. Try it on one blade, eg. using a Weld angle of 40 degree.
Try to avoid MeshToNurbs as it just creates one trimmed nurbs face for every mesh face. It will not help in this situation.