Let me know what you think of this plan, and let me know how I can get to those geometry classes.
CAD systems, on the other hand, require users to draw shapes perfectly the first time, and provide little ability to edit them after the fact.
I've only had some experience with Unigraphics in an engeneering class, but I don't recal it being hard to reposition pieces at all. It was my first time with a CAD program, so maybe I just got proficient at fixing my mistakes, or maybe it depends a lot on which program you're using.
I'd just like to have exact positioning features, even for doing art type things in Inkscape, it'd be nice to be able to precicely position things. I end up using snap-to-grid, and the alignment tools a lot right now, but if there were a way to precicely position things, I'd only have to draw some of my shapes once.
As for where the geometry is, I'm pretty new to the code, but in src/, sp-shape.h says "Base class for shapes, including <path> element", and sp-item.h says "Some things pertinent to all visible shapes".
Also, there are sp-spiral.cpp, sp-star.cpp, sp-rect.cpp etc. and sp-object-edit.cpp includes all the shapes .h files
Hope that helps. I'm new too,