Drop element Solid: What is "Smart Geometry & Bspline"? No very useful.

I could not find much info on the web on smart geometry. I was
making some 3d shapes and when i dropped the solid element, part of it
becames a smart geometry, part smart surface and part into a Bspline
(I am familiar with bspline in autocad). I am trying to get some
dimension from the smart element and bspline, but I am not sure if that
is possible. I find it useful info doing flat layouts of fancy
shapes by dropping element solid. Usually it gives me a arc or line,
but when it ends up with a smart geometry or a bspline, it's of no use
to me when it comes to getting dimensions of any type. Is there a
way to convert the Bspline into lines or arcs (something more usable)?
I found with the Bspline and smart geometry I can't use any Snaps. If
some one can explain this to me, I would appreciate it. thanks.