SOLVESPACE -- parametric 2d/3d CAD

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Some faces disappear when step rotating a segment (by Christopher A)

First of all, thanks for this great program.
It isn't often you encounter something as intuitive to use as this.

I've been trying to rotate a segment around a circle but this seems problematic. When I do this, a few faces often disappear, exposing the red insides of the segment.

It seems more likely to happen the more segments I have in the rotation, but sometimes it doesn't happen at all. And which faces it affects is also random, sometimes large segments, sometimes smaller ones.

Please find the two slvs files inside the attached zip file.
I would be very thankful if anyone could provide me with insight as to why this happens and how I can fix it.

Best Regards,
Thu May 8 2014, 16:33:06, download attachment
(no subject) (by Jonathan Westhues)
Thanks, I'm glad that you liked it.

I'm afraid this is the usual non-robustness of the NURBS code. Depending what you're doing, you may be able to make your problem go away by checking "force NURBS surfaces to triangle mesh" in the part file (segment.slvs).
Fri May 9 2014, 00:57:06
A work around (by Jonathan Jackson)
Good morning,

Here is a workaround you could try.

For the sake of ease I chose 24 segments to be my targeted number of segments.

Create your segment piece to specs and save assembly.
I used your original segment piece.

Next create an assembly of 8 segments.
-New window
-import segment assembly and constrain it to the diameter of the circle and to workplane point
-step rotate 8 times
-save assembly

Next create assembly of 24 segments
-New window
-Import 8 segment assembly, constrain to workplane point
-Import 8 segment assembly, constrain angle x axis of part and y axis of workplane to 15 degrees then constrain to center
-Import 8 segment assembly, constrain angle x axis of part and y axis of workplane to 30 degrees then constrain to center
-save assembly

See attached file for reference.

Tip, 360 degrees divided by the number of segments.

Sometimes when I get the missing faces I end up redoing the drawing in a completely different order and or importing parts in different orders.

Hope that helps a little.
Wed May 21 2014, 01:41:42, download attachment
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