What are the downsides of using TSplines with Rhino? Are there any as opposed to using Poly Surfaces and NURBS?
Pardon the stupid question, but do they render the same way?
Are there any properties that I should be aware of before I use them in an architectural model?
I might be a bit biased, but I think T-splines work pretty well with Rhino. Please take my advice with a grain of salt, I'm a developer (of T-splines) and not an architect. If you want better advice, I'd suggest asking on the rhino web newsgroup.
In my opinion, there are times that T-splines are worth the extra complication, and times that they are not.
For example, if you're trying to model really smooth organic surfaces, they are much simpler than NURBS with fillets to get really nice results. They're very similar to subdivision surfaces, so if that is the type of shape you're after then it's a good tool. For instance, Zaha Hadid has used T-splines for Rhino on several projects.
On the other hand, if you're making simple models, trying to do tightly dimensioned models, or need degrees other than 3, then they might not be worth it. Sometimes the NURBS conversion that you get out of T-splines is heavy and hard to work with, especially if you have a lot of star points.
T-splines can convert to poly surfaces / NURBS at any time, so they're pretty compatible. Most of the time they use their own mesher for speed, so they can look slightly different, but if that bothers you, you can convert to NURBS.
The main problems with them right now, IMHO, is that the creasing is not very good, and it's easy to make a very large model that uses a ton of RAM.
