Hello,
I was toying with some ideas for the 3D capabilities of Inkscape that will soon be developed. These ideas may have been floating around already, and I saw what the character Maximilian Albert proposed with the multiple Vanishing Points in his document for cubes in 3 space, and I figured it could be useful to apply to any style of primitive (such as cylinders, cones, etc...). Though, of course, with something such as a sphere, it would be rather awkward and pointeless, unless you consider an ellipsoid.
Which could lead into the idea of incorporating the VPs and 3D ability with the use of Bezier curves, possibly making a sort of moldable surface applicable to cubes, cylinders, and other such primitives. Another possibility being toyed with is the extension of freehand drawings - drawing any shape (closed or not, and including the calligraphy tool), and giving it depth, to which vanishing points can be applied to.
I'm not sure if these set of ideas would be considered over the top, or not in the direction the 3D project is aiming for. Of course, feedback and/or laughing is always encouraged. Thanks!