I need to export following face to SVG (see attachment). The face consists of one closed outer bspline and several inner circles. Because SVG does not support bspline, I work with sample points. The problem I have is the direction of the sample points (clockwise vs counterclockwise) in closed edges.
To get the sample points I use following code (I'm using the python wrapper PythonOCC):
curve, firstParam, lastParam = BRep_Tool_Curve(curEdge)
I loop through some points using
curve.Value(firstParam + dP) (dP representing incrementing values from firstParam to lastParam)
Sometimes the sample points of the outer and inner edges (contour and holes/bspline and circles in this case) are all in the same direction, sometimes (when examining other faces) I get the correct direction.
Are the first and last parameters of a curve always according to direction? In this example I get firstParam=0, lastParam=1 so I get the sample points by going from 0 to 1 (instead going from 1 to 0 gives the correct direction of the points). If not, how to get the sample points of a curve in the right order/direction? Or does there exist an easy way to export faces to SVG?
Thanks in advance