0D types
vertex/knot/vector (float,float,float)
1D types
arc/line (vertex,vertex)
2D types
polyforms
closed/open (bool, closed if the last/first vertex are identical, the last vertex is also dropped)
vertex (list[float], sequential list)
curves (all curves with non uniform radius are assumed to be NURBS)
closed/open (bool, closed if the last/first knot are identical, the last vertex is also dropped)
radius (radians) (float, if radius is set the curve is assumed to be constant radius)
knot & vector (dict(knot,vector))
3D types
solid
closed/open (boo, closed if the last/first vertex are identical, the last vertex is also dropped)
segment (list, polyforms and curves)