The Mid-Surface feature allows the creation of Surface bodies that are midway between existing Solid body faces. The resulting surface body/bodies have a Thickness property which defines the “thickness” that surface body represents. The faces can be manually selected, or an automatic mode allows you to set a thickness range and then automatically detect matching face pairs. Along with the basic name property, there are six properties for defining a Mid-Surface via manual selection, and four additional properties for automatic detection. Starting in release 12.1, the output bodies are grouped into parts based on the original bodies they came from.