No longer able to use STLs
I used to be able to import STLs and do unions with them, etc. (roughly 1
year ago on Debian 9)
I'm trying to import an STL and simply do a union with a cube.
The preview shows up fine, but when I render I don't see the STL.
I tried removing the union, no luck.
I tried moving the cube so it doesn't intersect with the STL, no luck.
I tried removing the union and moving the cube, no luck.
I tried three different but similar STLs, no luck.
Same issue every time.
I am using the version of OpenSCAD that ships with Debian 10 (2019.01) and I
also tried the app image version.
I tried all of the above debugging steps with both versions.
I tried swapping the union to a difference and I get:
ERROR: CGAL error in CGAL_Nef_polyhedron3(): CGAL ERROR: assertion
violation! Expr: e_below != SHalfedge_handle() File:
/usr/include/CGAL/Nef_3/SNC_FM_decorator.h Line: 427
and
ERROR: CGAL error in CGAL_Nef_polyhedron3(): CGAL ERROR: assertion
violation! Expr: pe_prev->is_border() ||
!internal::Plane_constructor<Plane>::get_plane(pe_prev->facet(),pe_prev->facet()->plane()).is_degenerate()
File: /usr/include/CGAL/Nef_3/polyhedron_3_to_nef_3.h Line: 251
for older and newer versions respectively.
Also seeing:
Error !!!!!!!!!!!!!!!!!!!!!!!
In the terminal. What sort of error message is that?
My STLs are all manifolds. There are no coincident faces. (Although this
really should not be an issue, as a 3d modeler I'm trying to match lines to
existing lines as best I can! I can offset by 0.1 if I really have to, but
that seems asinine)
I believe 2015.03 was the last version that worked for me, but unfortunately
there are no appimages for older releases.
How do I solve this issue? I have sunk so much time into learning OpenSCAD,
it's now useless for me. :(
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guaranteed_interwoven wrote
ERROR: CGAL error in CGAL_Nef_polyhedron3(): CGAL ERROR: assertion
violation! Expr: e_below != SHalfedge_handle() File:
/usr/include/CGAL/Nef_3/SNC_FM_decorator.h Line: 427
and
ERROR: CGAL error in CGAL_Nef_polyhedron3(): CGAL ERROR: assertion
violation! Expr: pe_prev->is_border() ||
!internal::Plane_constructor
<Plane>
::get_plane(pe_prev->facet(),pe_prev->facet()->plane()).is_degenerate()
File: /usr/include/CGAL/Nef_3/polyhedron_3_to_nef_3.h Line: 251
for older and newer versions respectively.
Also seeing:
Error !!!!!!!!!!!!!!!!!!!!!!!
In the terminal. What sort of error message is that?
My STLs are all manifolds. There are no coincident faces.
Those are CGAL errors, the tool used to render the geometry.
You get the error only when CGAL is called, so a import alone does not call
CGAL, but a union with a cube will.
Those error say CGAL is not happy with your STL, ie it is not valid.
e.g. assertion violation! Expr: e_below != SHalfedge_handle() is CGAL
checking the edge below is the same as the half edge.
Check for self-intersections.
If you share the STL I'll have a look at it.
Also seeing:
Error !!!!!!!!!!!!!!!!!!!!!!!
In the terminal. What sort of error message is that?
Could you post a screen capture, I've never seem anything like that.
Admin - email* me if you need anything, or if I've done something stupid...
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On 2020-04-17 06:33, guaranteed_interwoven wrote:
I used to be able to import STLs and do unions with them, etc. (roughly
1
year ago on Debian 9)
STL files are inherently troublesome and are not well suited for import
in other systems.
Try one of the available mesh repair tools such as e.g. MeshLab.
If you want more help you could make the offending STL available and I
can have a look at it using polyfix (part of AngelCAD).
Regards
Carsten Arnholm
On 17.04.20 06:33, guaranteed_interwoven wrote:
Also seeing:
Error !!!!!!!!!!!!!!!!!!!!!!!
In the terminal. What sort of error message is that?
That you have to ask the CGAL people:
https://github.com/CGAL/cgal/blob/master/Nef_3/include/CGAL/Nef_3/polygon_mesh_to_nef_3.h#L75-L106
ciao,
Torsten.
On 2020-04-17 15:37, Torsten Paul wrote:
On 17.04.20 06:33, guaranteed_interwoven wrote:
Also seeing:
Error !!!!!!!!!!!!!!!!!!!!!!!
In the terminal. What sort of error message is that?
That you have to ask the CGAL people:
https://github.com/CGAL/cgal/blob/master/Nef_3/include/CGAL/Nef_3/polygon_mesh_to_nef_3.h#L75-L106
Or you could read that code. It says the face normal is a null vector
after computing it with Newell's Method. It means there is a triangle in
the STL that is collapsed. Bad message, but that it what it means. That
can probably be fixed using one of the repair tools.
Carsten Arnholm
On Fri, Apr 17, 2020 at 03:37:25PM +0200, Torsten Paul wrote:
On 17.04.20 06:33, guaranteed_interwoven wrote:
Also seeing:
Error !!!!!!!!!!!!!!!!!!!!!!!
In the terminal. What sort of error message is that?
That you have to ask the CGAL people:
https://github.com/CGAL/cgal/blob/master/Nef_3/include/CGAL/Nef_3/polygon_mesh_to_nef_3.h#L75-L106
I've created a pull request.
https://github.com/CGAL/cgal/pull/4663
Roger.
--
** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** +31-15-2049110 **
** Delftechpark 11 2628 XJ Delft, The Netherlands. KVK: 27239233 **
The plan was simple, like my brother-in-law Phil. But unlike
Phil, this plan just might work.
Thank you for the help! This is driving me nuts. I used to be able to do
this sort of thing with OpenSCAD all day long and never run into an issue.
floor.stl http://forum.openscad.org/file/t2594/floor.stl
union()
{
translate([0, 0, 6])
scale([0.9842519685, 0.9842519685, 1])
import("floor.stl");
cube([50, 50, 6]);
}
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Self intersections, via NetFabb:
http://forum.openscad.org/file/t359/floor-si-Capture.jpg
Note also the thinner triangles to the left.
Unfortunately my Meshlab is crashing when I try anything with it...
Carsten?
Admin - email* me if you need anything, or if I've done something stupid...
- click on my MichaelAtOz label, there is a link to email me.
Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above.
--
Sent from: http://forum.openscad.org/
I used to be able to do this sort of thing with OpenSCAD all day long
and never run into an issue.
I think you must have just been lucky. OpenSCAD has never accepted broken
STLs and doesn't accept some valid ones and even some it has
produced itself.
Perhaps import should always try passing the mesh to CGAL, catch the
exception and report it is a broken STL. That would stop the endless
reports of "I can import my STL and it looks fine but CGS ops fail."
On Fri, 17 Apr 2020 at 23:43, MichaelAtOz oz.at.michael@gmail.com wrote:
Self intersections, via NetFabb:
http://forum.openscad.org/file/t359/floor-si-Capture.jpg
Note also the thinner triangles to the left.
Unfortunately my Meshlab is crashing when I try anything with it...
Carsten?
Admin - email* me if you need anything, or if I've done something
stupid...
- click on my MichaelAtOz label, there is a link to email me.
Unless specifically shown otherwise above, my contribution is in the
Public Domain; to the extent possible under law, I have waived all
copyright and related or neighbouring rights to this work. Obviously
inclusion of works of previous authors is not included in the above.
--
Sent from: http://forum.openscad.org/
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On Fri, Apr 17, 2020 at 05:21:43PM +0200, arnholm@arnholm.org wrote:
On 2020-04-17 15:37, Torsten Paul wrote:
On 17.04.20 06:33, guaranteed_interwoven wrote:
Also seeing:
Error !!!!!!!!!!!!!!!!!!!!!!!
In the terminal. What sort of error message is that?
That you have to ask the CGAL people:
https://github.com/CGAL/cgal/blob/master/Nef_3/include/CGAL/Nef_3/polygon_mesh_to_nef_3.h#L75-L106
Or you could read that code. It says the face normal is a null
vector after computing it with Newell's Method. It means there is a
triangle in the STL that is collapsed. Bad message, but that it what
it means. That can probably be fixed using one of the repair tools.
So it is a zero area triangle. Hmm.
I went ahead and improved the error message. I created a pull request,
and I was told it was accepted. (I don't see it under the link above).
But I thought STLs had normal vectors inside them and that the vector
compared there was from the file. You're saying it is computed and
indicates a zero-surface-area triangle?
Roger.
--
** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** +31-15-2049110 **
** Delftechpark 11 2628 XJ Delft, The Netherlands. KVK: 27239233 **
The plan was simple, like my brother-in-law Phil. But unlike
Phil, this plan just might work.