Correct me if I'm wrong on this.
I've worked with a lot of surfacing programs in the past, as well as parametric. We have an argument every few months about "solids" and "surfaces". I'm having a hard time getting the guys that have worked in Proe for years to understand that there is no such thing as a "solid" model unless you are running FEA or using a voxel based program.
A solid model is nothing more than "watertight" joined surfaces defining a closed volume. When you perform cuts, extrusions, etc. Creo is still caluculating boolean operations on surfaces. Explaining U/V paramaters falls on deaf ears. I won't even get into texuring or decals. 
So is there a way in Creo to show the isocurves of "solids/surfaces"? that's the only thing I can think of to prove my point. Any other suggestions to get my point across?