Question on STEP export parametric curves

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mike919
Posts: 1
Joined: Wed May 30, 2018 6:11 pm

Question on STEP export parametric curves

Post by mike919 »

Hi,

I've been using the freecad to export step files which are later read by some code that I have developed. I was excited to see that recently a new option was added in the step export options to write out surface edge curves in parametric space as well as 3d space. It seems like most programs such as solidworks only export to 3d space and I struggled for a long time how to get the edge curves in UV space.

So this is working great if the edge curve is a B spline, it seems that the end points always coincide with the beginning and end of the spline. My question is that when the parametric curve is just a line, it is given as a point and a direction but doesn't seem to define its end points in UV space. The end points will be only given in 3D space by the EDGE_CURVE element.

So what the best way of finding the endpoints for the parametric curve? I've had some success with computing the nurb inverse of the 3D end points to find UV coordinates, but this seems like an inelegant way of doing this. Hope I'm explaining this complicated question well enough. Thanks
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