Geom_BSplineCurve???

Hi All

From the OCC document, one of the rule for building a Geom_BSplinecurve is "on a periodic curve, the number of poles is equal to the sum of knot multiplicities, excluding the last knot". I donot understand it, Can someone tell me what it means?

I want to build a periodic curve.
the following is my data:

Pole: 11 Knot: 13 Order: 4 Degree: 3
Knot -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11
Multiplicities 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

m-aronsson's picture

Hi !

You say your knot vector size is 13, but you have 15 knots in the list, what is correct ?

Anyway, I have not used splines in OCC for some time so I don't rember how to set it up, but the idea with a periodic curve is that it is closed and it has a "smooth" shape, a circle for example could be a periodic curve, or if you prefer, the last degree CV should overlap the first degree CV.

Mikael