Getting Conic curve parameters

Hi, I am trying to read some curves from a Rhino file and I know that I am looking only for curves that were created as conics. There is an example (example link) on the main openNURBS page about reading ellipse parameters when they are only ON_curve_objects; how can I similarly know and extract parameters of a curve that was made as a conic curve?

Hi Sushrut,

Rhino does not have conic curves. It has NURBS curves that look like conic curves. For circles and ellipses, you can use ON_Curve::IsCircle and ON_Curve::IsEllipse to help figure out if the curve is a conic. But openNURBS has no tests for parabolas or hyperbolas.

Also, curves in openNURBS do not contain construction history. So there is no way to know how they were created. But you do have the full NURBS definition, which is helpful.

Perhaps you can explain what you are trying to do and why?

– Dale