If a rational periodic (U or V) bspline surface (i.e all weights = 1) is converted with SetVNotPeriodic or SetUNotPeriodic, it generates the wrong number of Poles/Knots
and a wrong Knot distribution.
I found (after much trying ) a workaround in the sources marked as
but seems like the bug is still there...
The workaround simply puts a weight (1,1) to 0.3 , does the conversion and then restores the weight to 1.0. It doest works well :)
At least put this in the documentation!!