Novedge Interviews Matt Sederberg

First, if you haven’t done it already, go over to the Novedge blog and read Franco Folini’s interview with Matt Sederberg. Most of my blog readers should know that Matt Sederberg is behind the T-Splines surfacing technology that can now be used as a plugin in Maya and Rhino.

I believe that the T-splines technology is part of the future of surface modeling. I’m not really a NURBS expert, but I believe NURBS is an open source technology used to describe solid and surface geometry. I don’t believe it has any particular owner. When a technology doesn’t have an owner, it cannot be driven to do more than it currently does, especially something as pervasive as NURBS. Of course in saying this, what I’m really hoping is that someone with accurate information will step in and save me from my own ignorance on the topic.

Here is a screen shot of the T-Splines toolbar inside the Rhino application. I’m just learning this combination. It has a vastly different type of workflow than SolidWorks, but for organic geometry, it’s a far better way to work than feature-based, history-based parametric modeling.

T splines in the end will be a competitor for NURBS, but right now it is just a complement. In the words of Matt S from the Novedge interview,

T-Splines is an excellent choice for organic free-form designs and they are a great complement to existing NURBS modeling techniques. In the future, we expect to overcome the remaining limitations and T-Splines will have the potential to completely replace NURBS in modeling applications.

Right now, T-Splines is only available as a plugin for Maya (a mesh modeler) and Rhino (a NURBS modeler). It is not available as a standalone CAD application. Maya and Rhino are vastly different from SolidWorks, and I am curious to know how T-Splines could be integrated into a sketch-based feature/history modeler. Both Rhino and T-splines work very well in the direct editing world of complex shapes, where you tug and pull points to create a shape often from a primitive such as a cube, cylinder or a sphere.

T-Splines stands apart in its compatibility with NURBS. Converting any T-Spline to NURBS surfaces is a push-button operation, as is converting any untrimmed NURBS to T-Splines.

Above is an image from the T-Splines site, illustrating some of the difference between T-Splines and Nurbs output from some modelers. Also from the T-Splines site is the following quote, talking about the compatibility of T-Splines with both NURBS and mesh modeling technology:

T-Splines also includes subdivision surface modeling attributes. Since T-Splines is a superset of both NURBS and subdivision surfaces, it converts losslessly from both surface types and can export to either NURBS or polygons. One significant benefit T-Splines enjoys over subdivision surfaces is that local detail can be added in T-Splines without changing the surface, while upon adding detail in subdivision surfaces the surface is slightly deformed.

Converting between mesh and NURBS is a big task. There are complete (and very expensive) software packages built around just that task. I haven’t yet actually tried it, but T-Splines seems to be a bridge between the two. Another huge strength of T-Splines over NURBS is that T-Splines can handle non-rectangular geometry better than NURBS. Star points in NURBS models are often referred to as degeneracies, and are usually avoided.

The benefit of surface modelers is that they give a high level of control over the surface being created, and this control often conflicts with simplicity

If I had done an interview with Matt, I would have asked something about mesh modeling and T-Splines acting as a bridge between mesh and NURBS. I also would have asked how or if T-Splines could be integrated usefully into a modeler like SolidWorks, and what if anything it would add to the parametric sketch-based modeling regime, or if it would limit its benefits to direct tug and pull modeling.

…we’ve created a simpler interface by allowing users to select faces and edges and move them around, Sketch-up style.

Anyway, I’ll leave more detail for another time. I’ve got T-Spline for Rhino running on my computer now, along with a user manual, so I should be able to do a bit of a review in the future at some point. Meanwhile, let’s try to imagine if you think T-Splines inside SolidWorks would be an exciting prospect.