Hi Mike,

> I know for one thing... Rhino's view of it's objects look really cluttered and
> bad with them, maybe there's some good uses for them.

The Rhino isocurve display thing is a side effect of Rhino being designed primarily for wireframe display mode, since I originally made it on a Pentium 90 machine way back when.


> So they're like the control-point grid, but on the surface?

Yeah, each isocurve is a 3D-space version of a horizontal or vertical 2D line in the UV space of the surface. Since a NURBS surface has a regular row/column grid layout to it, there is a kind of 2D rectangle built in to each surface as part of the surface definition.

- Michael