Tsplines
Ok, I can’t say that I completely understand what is going on here, but TSplines is the name of both a company and their technology. Tsplines is technology that sits on top of NURBS surface techniques, but it enables the multiple surface patches to be handled as a single continuous body. One of the methods it uses to do this is to enable partial isoparameter curves, so a T intersection between isoparameter curves could happen in the middle of the surface body rather than only at an edge.
Tsplines is available as a plugin for Maya or Rhino. For people who do non-parametric surface modeling, conceptually, this removes a lot of traditional modeling barriers. Working within the four-sided patch paradigm established by NURBS can be frustrating, and leads to unnaturally subdividing models into arbitrary faces. Tsplines doesn’t get you out of those requirements, but it does help you work within the requirements, treating the surface quilt as if it were a single face, enabling you to avoid bad transitions between faces.
Other cool stuff this can do is create a single edgeless shape over an existing set of surfaces, regardless of whether the surfaces touch or not, create NURBS surface over a mesh of points or curves (they claim as a “pushbutton” function). Also there are supposedly far fewer control points when using Tsplines, which obviously leads to a smoother model, but may present some control problems, although they claim that local detail can be added to a Tspline model.
Check out this video on CAD Junky for more info, or shlep on over to the TSplines website.
Would you like to see technology like this available in SolidWorks?