How to switch between flat and smooth shading through the Blender Python API

The flat/smooth shading mode is regulated through the “use_smooth” property of each polygon of the mesh.

To enable smooth shading we need to set the “use_smooth” property of each mesh polygon to “True”.

For active object:

bpy.context.object.data.polygons.foreach_set('use_smooth',  [True] * len(bpy.context.object.data.polygons))

1	bpy.context.object.data.polygons.foreach_set('use_smooth', [True] * len(bpy.context.object.data.polygons))

To enable flat shading – set the “use_smooth” property of each polygon to “False”.

bpy.context.object.data.polygons.foreach_set('use_smooth',  [False] * len(bpy.context.object.data.polygons))

1	bpy.context.object.data.polygons.foreach_set('use_smooth', [False] * len(bpy.context.object.data.polygons))

To make new shading mode visible – force update mesh data:

bpy.context.object.data.update()

1	bpy.context.object.data.update()