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problems with naked edges (by tom)
I'm a SolveSpace noob - I'd been trying to learn CAD with FreeCAD and had tons of trouble with it when I tried to build non-trivial parts that were meant to fit together. Mostly the problems resulted from fixing mistakes made "early" in my model tree would break everything that followed. As a beginner, of course, I was making many mistakes!

I was mostly using Sketcher/PartDesign in FC, so SolveSpace has been pretty straightforward to learn so far, and my 1st impression of the UI was deceptive in the sense that it looks bare-bones, but nothing I've reached for has been missing so far, and things have been pretty intuitive.

I've been running into issues where I'm getting naked edges in my models that have no intuitive (to me) explanation. I'd appreciate guidance as to why these are happening and techniques I can use to avoid them (or whether I'm hitting a bug!).

I'm attaching a zip with two files, each with a similar part that can demonstrate cases I've found.

"frame.slvs" has an extrusion based on nested rectangles, with a raised cylinder centered on a horizontal section, and some mis-aligned extruded text off to the side of the cylinder. This is a simplified example based on a real part I was making. If you make the diameter of the cylinder equal to the width of the frame, you get naked edges (you may need to "Show Naked Edges" to reveal them). If you shrink the cylinder, the issue resolves. Similarly, if you align the text with the frame edges, naked edges result. The group names have been changed to reflect where/how to make these changes.

"bar.slvs" was my attempt to simplify the example further, but this one behaves differently. Here there's a rectangular prism with both extruded text and a cylinder protruding from it. The circle can be the full "height" of the face it sits on, and the text can be aligned, without problem. However, if you narrow the bar a bit (while definitely leaving enough room for everything to fit!), naked edges appear.

Things I've tried:
- Monkeying around with dimensions/alignments
- Adjusting "chord tolerance"
- Adjusting "max piecewise linear segments"
- Setting "force NURBS surfaces to triangle mesh" on final group
- Different versions: v3.0.rc2+repack1-3 (this is the current Debian 11/bullseye package), and v3.1~flatpak (this is the current flatpak, again running under Debian 11)

I appreciate any advice/insight as to what's going on here!
Thu Mar 9 2023, 14:30:36, download attachment
(no subject) (by Andrew)
You have run into a known solver issue. The usual workaround to this and similar problems is to use 'force NURBS surfaces to triangle mesh' in the extrude group..

A common cause of such problems is curves in extrusions tangent to a face or edge, which may not show immediately, but cause a problem in latter extrusions. In your model, reducing the circle that is extruded to a diameter of 4.99 fixes the drawing without having to use the 'force...'..
Thu Mar 9 2023, 21:02:56
(no subject) (by ruevs)
Neither "bar.slvs" nor "frame.slvs" have naked edges for me.

This is with SolveSpace version 3.1~659215d8. But there have been no recent changes that should impact this.

What is your chord tolerance?
Wed Mar 22 2023, 04:51:47
(no subject) (by Andrew)
Using version 3,1-70bde63c on Manjaro, I get naked edges with the original file using analyze or when exporting to STL. Modifying the file as in the fixed version attached, which was reducing the diameter of the extruded circle from 5 to 4.99 fixed the problem. It is worth noting that analyze sows no errors when run on the group g006 of the original version.
Wed Mar 22 2023, 12:11:26, download attachment bar-fixed.stl
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