[Gmsh] The Control of OCC BSpline points on the intersection edge

Jun Fang hapfang at gmail.com
Tue Mar 10 17:55:10 CET 2020


Dear GMSH users,

By applying the BooleanIntersection between a volume and a curved surface,
I can get a decent BSpline intersection curve loop on the surface. The
problem I am facing is that the BooleanIntersection by default gives me an
“extra” point on the intersection edge, which I don’t want (for good
reasons). A screenshot is posted below. The ‘Cylinder 23(OCC)’ is the
outcome of Boolean intersection. What I need are the four points (22, 23,
24, 25) and four associated BSpline curves on the Surface. Somehow, I
couldn’t get rid of the extra point (26), which is located at the z max
position of Surface 23(OCC). My guess is that the additional point is kinda
of a *reference point* created by the BooleanIntersection function.

Is it possible to workaround this issue? I know Compound BSpline could
potentially merge curves (i.e. connecting BSplines 27 and 28 here into
one), but it only works for the built-in CAD kernel. Is there an equivalent
function for OCC kernel? Any comments/suggestions are appreciated.

[image: image.png]

Thanks very much,

Jun
-- 
*Jun Fang, Ph.D. - **Argonne **National Laboratory **- **(630)252-4561*
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