GH Horizontal curves oriented into XY plane wrongly

Hi there!
I am trying to get the intersection between a Brep and a plane, and then orient the intersection into a XY plane. The Brep has a horizontal surface, and the trimming plane has its normal vector horizontal, so I expect to get the intersection curve as a horizontal curve in my XY plane. But it has some slope and I can not see why.

Can anybody help me? What am I doing or assuming wrong? Or why aren’t they horizontal on XY?

I already checked that:

  • Trimming planes have its Y vector vertical
  • Destiny planes have Y vector oriented as 0,1,0
  • I also checked the intersection with horizontal planes (instead of my Brep) and I got the same result.

Thanks! (18.1 KB)


Nope. Dot product is not equal to 1.
Use Align Plane.

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