In a recent support call, one of our Inventor customers wanted to place a dimension on a theoretical point. He wanted to dimension a diameter of a tapered hole from the outside surface that was consumed by a chamfer on that same hole. Below is an example of the situation, and the dimension he was trying to create.
Here is a quick set of commands to add a surface to an existing solid part. We will start with a simple 6X10X1 inch box: