xNURBS V5.1 is powered by xn kernel 2021.1.1, which includes a number of enhancements.
1. The most important improvement is that v5.1 significantly reduces the deviation, and the deviation achieved by V5.1 can be easily 10 times smaller compared with the previous version. (For the car side mirror below, V5.1 generates a model with 0.00059 mm of G0 deviation and 0.04 degree of G1 deviation. As a comparison, with the exactly same model and the same xNURBS setting for V5, the G0 deviation is 0.00997 mm and the G1 deviation is 0.4 degree.)
Car Side Mirror: All surfaces of the car side mirror are generated by XNurbs. Watch the tutorial video of modeling car side mirror:
For the detailed improvement of V5.1, please refer to xNURBS manual.