One thing I'd like to see:

Instead of having to define the quant2meter and meter2quant, and having to define the newtonworld struct instance I'd like to see a proper get/set function interface.

Meaning newtonworld is defined inside the wrapper files, and I have some sort of Newton_getWorld() function to return the pointer.
Same goes for the conversion factors, maybe a function like Newton_setMetertoquant() or so...

I'm currently trying to get some proper hinge setup working. If I end up with something useful I maybe post the code here and you can decide whether you want to take it over to the wrapper or not.

Depends on how generic it will get...


Also maybe it makes sense to dd a function which generates an ANGLE from a matrix and converts an ANGLE back to a matrix, without being tied to an entity.
Currently I have the problem that Newton expects a quaternion, I still have to look up how it is defined and how this has to be set in order to get the correct behaviour.