Hi Nick, yes like Stefan writes above it looks like you're not getting vertex normals coming through.

In C4D look under Edit > Preferences > Import/Export > "Wavefront Import" and make sure "Import Normals" is checked.

You want to make sure the object is shaded using the vertex normals that are stored in the .obj file, those normals come from the original NURBS surfaces and help make the rendered polygons have the same shading behavior as the original CAD model.

If the vertex normals are discarded and instead created by averaging polygon faces it usually results in the type of artifacts that you're showing there.

- Michael