Just noticed this from another software’s forum which had this feature before Autodesk bought it and shut it down (well, it’s still available in Fusion 360):
I’m guessing adapting this for Catmull-Clark SubD isn’t straightforward, but at least Autodesk can’t stop anyone from trying now! One can almost say that Blender is partway there with their ngon support…
Like always i’m puzzled aboout patents because:
and this is showing how to convert it to somethign else…(so then no paten involved ??)
Maybe the patent is/was teh reason why cycles adaptive subdivision was “experimental” ??
So: Is this really needed when people (like also McNeel) just used soemthing different for years… ??
( If someone doesn’t get the intial form then any “refinement” will not help anyway… 
)
One thing that has always kept me away from looking at NURBS in Blender was my knowledge that this patent existed. I’m glad it is now in the publiic domain!
But Non-uniform rational basis splines aren’t patented… and it’s more that they aren’t very well evolved for this polygon modeler of blender… 
Is adaptive subdivision in other render engines T-Spline based (because I thought the ability do this was simply a part of OpenSubDiv which is already compatible with Blender’s license)? It does not seem to make sense to me because there is no indication Mai (the coder who fleshed out rendertime subdivision) stopped her work because of potential legal issues (as opposed to meeting personal needs and not having the spare time to go further).
The almost funny thing is… to subdivide between to points of a curve or a surface… in the math world there are some posibilities starting with linear… non of them are “inventions” they are only possibities… and if someone thinks about this… then proberly will “find” some solution someone may have discovered already… and to put a patent on this… 
<sarcasm>
“So you come to the conclusion that 1 and 1 is 2 ?? Fine… now you have to pay me for this because i have the patent on addition…”
</sarcasm>