Blender: improve import Material generation

cg/blender/import_cad/import_materials.py

@@ -74,6 +74,12 @@ def assign_materials(bobj, fem_mat):
         principled.roughness = rg
         principled.emission_color = e_col
         principled.alpha = alpha
+        bevel = bmat.node_tree.nodes.new(type="ShaderNodeBevel")
+        bevel.location = -300, -300
+        bevel.samples = 32
+        bevel.inputs[0].default_value = 0.001
+        principled_node = bmat.node_tree.nodes["Principled BSDF"]
+        bmat.node_tree.links.new(bevel.outputs['Normal'], principled_node.inputs['Normal'])
         # prepare for reimport
         if len(bobj.material_slots) < 1:
             bobj.data.materials.append(bmat)