Point3d cent = new Point3d(0, 0, 0);
Curve c1 = crv.Extend(CurveEnd.Start, CurveExtensionStyle.Line, cent);
A = c1;
extend_null.gh (2.8 KB)
your polyline can t be extended with a tangent line to go through 0,0,0.
try other CurveExtensionStyles
or extend by length:
https://developer.rhino3d.com/api/rhinocommon/rhino.geometry.curve/extend#(curveend,double,curveextensionstyle)
extend_null_tp.gh (7.0 KB)
hope this helps - kind regards - tom
thank you