This property represents an angle in degrees for a threshold value between face normals on a
articles/3D Modeling with Parts|solid modeled part. If the normal difference is less than the value, normals will be adjusted to smooth the difference. Usually a value between 30 and 70 degrees will produce a good result. 0 degrees leads to sharp edges. Values between 90 and 180 degrees are allowed but not encouraged, as it may cause a “shadowing” effect on unions with sharp edges.
Note that smoothing will not affect the normals between different materials or different colors.