Vertex maps in polygons

Is there a way to switch this off? there is only the way in Rhino to flat shade meshes, in render applications this would result in distortions, thanks!

I think you have almost 2 solutions, or you Unweld the mesh, so normals will no more be interpolated or you can transform this mesh to a Brep.

@laurent_delrieu thank you, unweld does the trick.