Hi Michael,

I haven't had any 'trouble' as such, but I have had issues where my sub-d models have had to be re-edited after conversion because, for example, a circle of a set diameter was very slightly out even though it looked fine by eye. Due to the stretchy nature of sub-d's it's extremely difficult to get cad-accurate results. Bearing in mind I mainly build models of bottles, which must be symmetrical for manufacture.
For example the indentation on the bottle above is perfectly circular in the MOI one but the sub-d one is slightly off due to the difficulty of faking a boolean cut across a curved surface.

Recently a client needed to edit the radii on the neck of an odd shaped bottle that I'd build in modo. He'd specified one size that later needed changing. Normally he could just tweak this himself in something like Spaceclaim, but because T-Splines had patched over all the radii, instead of retaining them, he had to send it back to me to regenerate. He wasn't too happy about it.

I still use t-splines though as it really is very clever. I often end up with a hybrid model that has a sub-d body and a cad neck. Having MOI handy makes that kind of thing very easy. Horses for courses I guess.

cheers
Roger