Blender provides many operators and utilities for determining how to treat or calculate normals of a mesh. The two main treatments for normals are the “Shade Flat” and “Shade Smooth” operators. These operators are available in both the object context menu, where they can be applied to a whole object, or in the edit mesh mode where they are only applied to the current face selection.
Many meshes may require a mix of the two shading treatments in order to achieve a desired render. This is particularly true for hard surface or mechanical objects, but the solution is not made immediately clear in Blender’s current UI. This leads to some people using tools like the Edge Split modifier to achieve the desired effect. However, a better solution is Blender’s own Auto Smooth filter, which is tucked away in the “Normals” panel in the “Object Data” properties of a mesh object.
We decided it was time that this functionality be available as its own operator and made available in the object mode context menu, right above the “Shade Flat” and “Shade Smooth” options. This new operator sets the shading mode of the object to smooth and allows you to quickly define the angle limit for the sharper corners of your mesh.
When using the autosmooth operator, you can expand the tool settings to to set the angle limit for smoothing.