Double Sided Surfaces

Double sided surfaces are created from 1 or more surfaces of an object.  To create a double sided surface select Surface A and use Surface: Create Double Sided Surface(s) menu option. 

Extruding a Double Sided Surface

Double sided surfaces can be extruded to a Solid using Solid: Extrude to Solid menu option.  Note: Only a single surface can be extruded.

Example double sided surface and extrude to Solid feature

Measuring Distance using Parallel Planes

When selected Surface A and Surface B are parallel distance between 2 planes will be shown in status bar.  To measure distance between non-parallel surfaces or any space create two double sided surfaces from an existing object (i.e. rectangle side) that are parallel and move them into position.  Select one as Surface A and the other as Surface B to get distance.