> One of the difficulties though is that sub-d / box modeling has a fairly
> different kind of toolset than NURBS modeling, so it would mean introducing
> quite a number of brand new tools to work on the polygon cage. That means
> it will take quite a bit of work and that's why I don't know when it will happen.

Well, you could just make it more generalized then. MoI already has the ability to push and pull points, curves, and surfaces, with and without the precise transform tools. Thus editing a sub-d cage would be very much like editing the hull cage of a surface now. If the purpose is to use this cage to generate NURBS surfaces, then the only real additional tools I could see as being needed would be a fast way to add edge loops and some loop and ring selection. And even these tools would be of use for NURBS work; adding a loop to a surface would just be a very fast trim and such.

The workflow I envision would be two ways of entering into this sort of cage edit. One would be to create a box (that would be making a sphere). The next would be to do something akin to the Network tool, only you end up with a cage controlling the surface instead of the surface directly. From there you could pull the points and edges around, use the new tool to add loops, and box model your way around. Tools like Extrude or Chamfer would work off a face or an edge much the same as it does on NURBS surfaces. The tools that can't work on a surface or solid would likewise not work on a cage. And I don't really think it'd be safe or wise to let Booleans work on them (way too messy to make it work consistently).

Once you like it, you could then drop the cage down to a surface and have a nice, smooth NURBS surface made from the more gooey and sculpture sub-d methodology. It wouldn't really be a full-fledged subdivision modeling solution, but that isn't a big deal I don't think.

Ideally, one could also take a surface and push the same Cage Create button and get a lower-res cage around that surface (or even solid). One of the main issues I have with trying to push or pull surfaces generated in MoI from lofts, sweeps, or networks is that the control point density is often huge. Without a soft-selection or free-form deformation cage, modifying these surfaces naturally is a pain. There's also no way to deform things (like a bend or twist) without doing it the very tedious and unnatural way (moving point by point). If I could just toss on a cage, such things would be cake; add in a soft-selection falloff and I think I'd be in heaven.