I noticed that if I make my model in the snapshot 2025.04.29.snap that when I load it into prusaslicer it says it's correcting 1796 errors. If I make my stl in the same program but enable CGAL then it says "no errors detected". That doesn't seem ideal. Anybody know why this is happening?

> On May 15, 2025, at 18:31, Adrian Mariano via Discuss <discuss@lists.openscad.org> wrote: > > I noticed that if I make my model in the snapshot 2025.04.29.snap that when I load it into prusaslicer it says it's correcting 1796 errors. If I make my stl in the same program but enable CGAL then it says "no errors detected". That doesn't seem ideal. Anybody know why this is happening? Can you share a smallish example? My best cold guess would be that Prusaslicer cannot handle the precision of the vertices and ends up merging close vertices causing zero area triangles and it complains. Such repairs are _typically_ benign, unless they cause topology collapse. Bad news is that there is no general solution to fix this; even with a native solution in OpenSCAD, you’d eventually have to make destructive changes to topology if you need to limit vertex precision. -Marius

The example is a single hinge part produced from BOSL2. Is that small enough? Why would there be a difference in vertex precision between manifold and CGAL? On Thu, May 15, 2025 at 9:10 PM Marius Kintel <marius@kintel.net> wrote: > On May 15, 2025, at 18:31, Adrian Mariano via Discuss < > discuss@lists.openscad.org> wrote: > > I noticed that if I make my model in the snapshot 2025.04.29.snap that > when I load it into prusaslicer it says it's correcting 1796 errors. If I > make my stl in the same program but enable CGAL then it says "no errors > detected". That doesn't seem ideal. Anybody know why this is happening? > > > Can you share a smallish example? > My best cold guess would be that Prusaslicer cannot handle the precision > of the vertices and ends up merging close vertices causing zero area > triangles and it complains. Such repairs are _typically_ benign, unless > they cause topology collapse. > Bad news is that there is no general solution to fix this; even with a > native solution in OpenSCAD, you’d eventually have to make destructive > changes to topology if you need to limit vertex precision. > > -Marius > >

Due to limitations in CGAL, we have to quantize vertices when moving between OpenSCAD and CGAL, and when exporting from CGAL. This causes vertices to have less precision, but at the risk of making destructive topology changes. With Manifold, we have a more robust pipeline and can maintain the natural (64-bit doubles) vertex precision end-to-end. -Marius > On May 15, 2025, at 21:32, Adrian Mariano <avm4@cornell.edu> wrote: > > The example is a single hinge part produced from BOSL2. Is that small enough? > > Why would there be a difference in vertex precision between manifold and CGAL? > > On Thu, May 15, 2025 at 9:10 PM Marius Kintel <marius@kintel.net <mailto:marius@kintel.net>> wrote: >>> On May 15, 2025, at 18:31, Adrian Mariano via Discuss <discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>> wrote: >>> >>> I noticed that if I make my model in the snapshot 2025.04.29.snap that when I load it into prusaslicer it says it's correcting 1796 errors. If I make my stl in the same program but enable CGAL then it says "no errors detected". That doesn't seem ideal. Anybody know why this is happening? >> >> Can you share a smallish example? >> My best cold guess would be that Prusaslicer cannot handle the precision of the vertices and ends up merging close vertices causing zero area triangles and it complains. Such repairs are _typically_ benign, unless they cause topology collapse. >> Bad news is that there is no general solution to fix this; even with a native solution in OpenSCAD, you’d eventually have to make destructive changes to topology if you need to limit vertex precision. >> >> -Marius >>

Is the hinge model a small enough example or do I need to try to reduce it somehow? On Thu, May 15, 2025 at 9:35 PM Marius Kintel <marius@kintel.net> wrote: > Due to limitations in CGAL, we have to quantize vertices when moving > between OpenSCAD and CGAL, and when exporting from CGAL. This causes > vertices to have less precision, but at the risk of making destructive > topology changes. With Manifold, we have a more robust pipeline and can > maintain the natural (64-bit doubles) vertex precision end-to-end. > > -Marius > > On May 15, 2025, at 21:32, Adrian Mariano <avm4@cornell.edu> wrote: > > The example is a single hinge part produced from BOSL2. Is that small > enough? > > Why would there be a difference in vertex precision between manifold and > CGAL? > > On Thu, May 15, 2025 at 9:10 PM Marius Kintel <marius@kintel.net> wrote: > >> On May 15, 2025, at 18:31, Adrian Mariano via Discuss < >> discuss@lists.openscad.org> wrote: >> >> I noticed that if I make my model in the snapshot 2025.04.29.snap that >> when I load it into prusaslicer it says it's correcting 1796 errors. If I >> make my stl in the same program but enable CGAL then it says "no errors >> detected". That doesn't seem ideal. Anybody know why this is happening? >> >> >> Can you share a smallish example? >> My best cold guess would be that Prusaslicer cannot handle the precision >> of the vertices and ends up merging close vertices causing zero area >> triangles and it complains. Such repairs are _typically_ benign, unless >> they cause topology collapse. >> Bad news is that there is no general solution to fix this; even with a >> native solution in OpenSCAD, you’d eventually have to make destructive >> changes to topology if you need to limit vertex precision. >> >> -Marius >> >> >

Not sure, but if you share it I can have a look. Do you also have an easy way to reproduce? I’m not familiar with Prusaslicer. -Marius > On May 15, 2025, at 21:47, Adrian Mariano <avm4@cornell.edu> wrote: > > Is the hinge model a small enough example or do I need to try to reduce it somehow? > > > On Thu, May 15, 2025 at 9:35 PM Marius Kintel <marius@kintel.net <mailto:marius@kintel.net>> wrote: >> Due to limitations in CGAL, we have to quantize vertices when moving between OpenSCAD and CGAL, and when exporting from CGAL. This causes vertices to have less precision, but at the risk of making destructive topology changes. With Manifold, we have a more robust pipeline and can maintain the natural (64-bit doubles) vertex precision end-to-end. >> >> -Marius >> >>> On May 15, 2025, at 21:32, Adrian Mariano <avm4@cornell.edu <mailto:avm4@cornell.edu>> wrote: >>> >>> The example is a single hinge part produced from BOSL2. Is that small enough? >>> >>> Why would there be a difference in vertex precision between manifold and CGAL? >>> >>> On Thu, May 15, 2025 at 9:10 PM Marius Kintel <marius@kintel.net <mailto:marius@kintel.net>> wrote: >>>>> On May 15, 2025, at 18:31, Adrian Mariano via Discuss <discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>> wrote: >>>>> >>>>> I noticed that if I make my model in the snapshot 2025.04.29.snap that when I load it into prusaslicer it says it's correcting 1796 errors. If I make my stl in the same program but enable CGAL then it says "no errors detected". That doesn't seem ideal. Anybody know why this is happening? >>>> >>>> Can you share a smallish example? >>>> My best cold guess would be that Prusaslicer cannot handle the precision of the vertices and ends up merging close vertices causing zero area triangles and it complains. Such repairs are _typically_ benign, unless they cause topology collapse. >>>> Bad news is that there is no general solution to fix this; even with a native solution in OpenSCAD, you’d eventually have to make destructive changes to topology if you need to limit vertex precision. >>>> >>>> -Marius >>>> >>

I guess you can try Meshlab as well. Also, maybe try 3mf, it should preserve the topology information. On Fri, May 16, 2025, 9:58 AM Marius Kintel via Discuss < discuss@lists.openscad.org> wrote: > Not sure, but if you share it I can have a look. > > Do you also have an easy way to reproduce? I’m not familiar with > Prusaslicer. > > -Marius > > On May 15, 2025, at 21:47, Adrian Mariano <avm4@cornell.edu> wrote: > > Is the hinge model a small enough example or do I need to try to reduce it > somehow? > > > On Thu, May 15, 2025 at 9:35 PM Marius Kintel <marius@kintel.net> wrote: > >> Due to limitations in CGAL, we have to quantize vertices when moving >> between OpenSCAD and CGAL, and when exporting from CGAL. This causes >> vertices to have less precision, but at the risk of making destructive >> topology changes. With Manifold, we have a more robust pipeline and can >> maintain the natural (64-bit doubles) vertex precision end-to-end. >> >> -Marius >> >> On May 15, 2025, at 21:32, Adrian Mariano <avm4@cornell.edu> wrote: >> >> The example is a single hinge part produced from BOSL2. Is that small >> enough? >> >> Why would there be a difference in vertex precision between manifold and >> CGAL? >> >> On Thu, May 15, 2025 at 9:10 PM Marius Kintel <marius@kintel.net> wrote: >> >>> On May 15, 2025, at 18:31, Adrian Mariano via Discuss < >>> discuss@lists.openscad.org> wrote: >>> >>> I noticed that if I make my model in the snapshot 2025.04.29.snap that >>> when I load it into prusaslicer it says it's correcting 1796 errors. If I >>> make my stl in the same program but enable CGAL then it says "no errors >>> detected". That doesn't seem ideal. Anybody know why this is happening? >>> >>> >>> Can you share a smallish example? >>> My best cold guess would be that Prusaslicer cannot handle the precision >>> of the vertices and ends up merging close vertices causing zero area >>> triangles and it complains. Such repairs are _typically_ benign, unless >>> they cause topology collapse. >>> Bad news is that there is no general solution to fix this; even with a >>> native solution in OpenSCAD, you’d eventually have to make destructive >>> changes to topology if you need to limit vertex precision. >>> >>> -Marius >>> >>> >> > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >

Ok. I've got a small example, but you will unfortunately have to update to the latest BOSL2 to run it. I discovered the issue while developing a print-in-place hinge for BOSL2, so it occurs with a just-added new feature. include<BOSL2/std.scad> include<BOSL2/hinges.scad> $fn=32; knuckle_hinge(length=25, segs=3, offset=3, inner=true, in_place=true); The model looks like this: [image: image.png] The STL file is small, so I'm attaching it as well. Maybe someone with other software than PrusaSlicer can tell us what's wrong with the model without having to mess with BOSL2. With this model PrusaSlicer reports "Auto-repaired 256 errors". On Thu, May 15, 2025 at 10:34 PM pca006132 <john.lck40@gmail.com> wrote: > I guess you can try Meshlab as well. > > Also, maybe try 3mf, it should preserve the topology information. > > On Fri, May 16, 2025, 9:58 AM Marius Kintel via Discuss < > discuss@lists.openscad.org> wrote: > >> Not sure, but if you share it I can have a look. >> >> Do you also have an easy way to reproduce? I’m not familiar with >> Prusaslicer. >> >> -Marius >> >> On May 15, 2025, at 21:47, Adrian Mariano <avm4@cornell.edu> wrote: >> >> Is the hinge model a small enough example or do I need to try to reduce >> it somehow? >> >> >> On Thu, May 15, 2025 at 9:35 PM Marius Kintel <marius@kintel.net> wrote: >> >>> Due to limitations in CGAL, we have to quantize vertices when moving >>> between OpenSCAD and CGAL, and when exporting from CGAL. This causes >>> vertices to have less precision, but at the risk of making destructive >>> topology changes. With Manifold, we have a more robust pipeline and can >>> maintain the natural (64-bit doubles) vertex precision end-to-end. >>> >>> -Marius >>> >>> On May 15, 2025, at 21:32, Adrian Mariano <avm4@cornell.edu> wrote: >>> >>> The example is a single hinge part produced from BOSL2. Is that small >>> enough? >>> >>> Why would there be a difference in vertex precision between manifold and >>> CGAL? >>> >>> On Thu, May 15, 2025 at 9:10 PM Marius Kintel <marius@kintel.net> wrote: >>> >>>> On May 15, 2025, at 18:31, Adrian Mariano via Discuss < >>>> discuss@lists.openscad.org> wrote: >>>> >>>> I noticed that if I make my model in the snapshot 2025.04.29.snap that >>>> when I load it into prusaslicer it says it's correcting 1796 errors. If I >>>> make my stl in the same program but enable CGAL then it says "no errors >>>> detected". That doesn't seem ideal. Anybody know why this is happening? >>>> >>>> >>>> Can you share a smallish example? >>>> My best cold guess would be that Prusaslicer cannot handle the >>>> precision of the vertices and ends up merging close vertices causing zero >>>> area triangles and it complains. Such repairs are _typically_ benign, >>>> unless they cause topology collapse. >>>> Bad news is that there is no general solution to fix this; even with a >>>> native solution in OpenSCAD, you’d eventually have to make destructive >>>> changes to topology if you need to limit vertex precision. >>>> >>>> -Marius >>>> >>>> >>> >> _______________________________________________ >> OpenSCAD mailing list >> To unsubscribe send an email to discuss-leave@lists.openscad.org >> >

Just out of curiosity, could you export it as an OBJ file and see what PrusaSliser reports? On Fri, May 16, 2025 at 5:53 PM Adrian Mariano via Discuss < discuss@lists.openscad.org> wrote: > Ok. I've got a small example, but you will unfortunately have to update > to the latest BOSL2 to run it. I discovered the issue while developing a > print-in-place hinge for BOSL2, so it occurs with a just-added new > feature. > > include<BOSL2/std.scad> > include<BOSL2/hinges.scad> > > $fn=32; > knuckle_hinge(length=25, segs=3, offset=3, inner=true, in_place=true); > > The model looks like this: > > [image: image.png] > > The STL file is small, so I'm attaching it as well. Maybe someone with > other software than PrusaSlicer can tell us what's wrong with the model > without having to mess with BOSL2. With this model PrusaSlicer reports > "Auto-repaired 256 errors". > > On Thu, May 15, 2025 at 10:34 PM pca006132 <john.lck40@gmail.com> wrote: > >> I guess you can try Meshlab as well. >> >> Also, maybe try 3mf, it should preserve the topology information. >> >> On Fri, May 16, 2025, 9:58 AM Marius Kintel via Discuss < >> discuss@lists.openscad.org> wrote: >> >>> Not sure, but if you share it I can have a look. >>> >>> Do you also have an easy way to reproduce? I’m not familiar with >>> Prusaslicer. >>> >>> -Marius >>> >>> On May 15, 2025, at 21:47, Adrian Mariano <avm4@cornell.edu> wrote: >>> >>> Is the hinge model a small enough example or do I need to try to reduce >>> it somehow? >>> >>> >>> On Thu, May 15, 2025 at 9:35 PM Marius Kintel <marius@kintel.net> wrote: >>> >>>> Due to limitations in CGAL, we have to quantize vertices when moving >>>> between OpenSCAD and CGAL, and when exporting from CGAL. This causes >>>> vertices to have less precision, but at the risk of making destructive >>>> topology changes. With Manifold, we have a more robust pipeline and can >>>> maintain the natural (64-bit doubles) vertex precision end-to-end. >>>> >>>> -Marius >>>> >>>> On May 15, 2025, at 21:32, Adrian Mariano <avm4@cornell.edu> wrote: >>>> >>>> The example is a single hinge part produced from BOSL2. Is that small >>>> enough? >>>> >>>> Why would there be a difference in vertex precision between manifold >>>> and CGAL? >>>> >>>> On Thu, May 15, 2025 at 9:10 PM Marius Kintel <marius@kintel.net> >>>> wrote: >>>> >>>>> On May 15, 2025, at 18:31, Adrian Mariano via Discuss < >>>>> discuss@lists.openscad.org> wrote: >>>>> >>>>> I noticed that if I make my model in the snapshot 2025.04.29.snap >>>>> that when I load it into prusaslicer it says it's correcting 1796 errors. >>>>> If I make my stl in the same program but enable CGAL then it says "no >>>>> errors detected". That doesn't seem ideal. Anybody know why this is >>>>> happening? >>>>> >>>>> >>>>> Can you share a smallish example? >>>>> My best cold guess would be that Prusaslicer cannot handle the >>>>> precision of the vertices and ends up merging close vertices causing zero >>>>> area triangles and it complains. Such repairs are _typically_ benign, >>>>> unless they cause topology collapse. >>>>> Bad news is that there is no general solution to fix this; even with a >>>>> native solution in OpenSCAD, you’d eventually have to make destructive >>>>> changes to topology if you need to limit vertex precision. >>>>> >>>>> -Marius >>>>> >>>>> >>>> >>> _______________________________________________ >>> OpenSCAD mailing list >>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>> >> _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >

So, I did that. STL file: 932 facets, 256 errors OBJ file: 1060 facets, 0 errors On Fri, May 16, 2025 at 6:02 PM Leonard Martin Struttmann < lenstruttmann@gmail.com> wrote: > Just out of curiosity, could you export it as an OBJ file and see what > PrusaSliser reports? > > > On Fri, May 16, 2025 at 5:53 PM Adrian Mariano via Discuss < > discuss@lists.openscad.org> wrote: > >> Ok. I've got a small example, but you will unfortunately have to update >> to the latest BOSL2 to run it. I discovered the issue while developing a >> print-in-place hinge for BOSL2, so it occurs with a just-added new >> feature. >> >> include<BOSL2/std.scad> >> include<BOSL2/hinges.scad> >> >> $fn=32; >> knuckle_hinge(length=25, segs=3, offset=3, inner=true, in_place=true); >> >> The model looks like this: >> >> [image: image.png] >> >> The STL file is small, so I'm attaching it as well. Maybe someone with >> other software than PrusaSlicer can tell us what's wrong with the model >> without having to mess with BOSL2. With this model PrusaSlicer reports >> "Auto-repaired 256 errors". >> >> On Thu, May 15, 2025 at 10:34 PM pca006132 <john.lck40@gmail.com> wrote: >> >>> I guess you can try Meshlab as well. >>> >>> Also, maybe try 3mf, it should preserve the topology information. >>> >>> On Fri, May 16, 2025, 9:58 AM Marius Kintel via Discuss < >>> discuss@lists.openscad.org> wrote: >>> >>>> Not sure, but if you share it I can have a look. >>>> >>>> Do you also have an easy way to reproduce? I’m not familiar with >>>> Prusaslicer. >>>> >>>> -Marius >>>> >>>> On May 15, 2025, at 21:47, Adrian Mariano <avm4@cornell.edu> wrote: >>>> >>>> Is the hinge model a small enough example or do I need to try to reduce >>>> it somehow? >>>> >>>> >>>> On Thu, May 15, 2025 at 9:35 PM Marius Kintel <marius@kintel.net> >>>> wrote: >>>> >>>>> Due to limitations in CGAL, we have to quantize vertices when moving >>>>> between OpenSCAD and CGAL, and when exporting from CGAL. This causes >>>>> vertices to have less precision, but at the risk of making destructive >>>>> topology changes. With Manifold, we have a more robust pipeline and can >>>>> maintain the natural (64-bit doubles) vertex precision end-to-end. >>>>> >>>>> -Marius >>>>> >>>>> On May 15, 2025, at 21:32, Adrian Mariano <avm4@cornell.edu> wrote: >>>>> >>>>> The example is a single hinge part produced from BOSL2. Is that small >>>>> enough? >>>>> >>>>> Why would there be a difference in vertex precision between manifold >>>>> and CGAL? >>>>> >>>>> On Thu, May 15, 2025 at 9:10 PM Marius Kintel <marius@kintel.net> >>>>> wrote: >>>>> >>>>>> On May 15, 2025, at 18:31, Adrian Mariano via Discuss < >>>>>> discuss@lists.openscad.org> wrote: >>>>>> >>>>>> I noticed that if I make my model in the snapshot 2025.04.29.snap >>>>>> that when I load it into prusaslicer it says it's correcting 1796 errors. >>>>>> If I make my stl in the same program but enable CGAL then it says "no >>>>>> errors detected". That doesn't seem ideal. Anybody know why this is >>>>>> happening? >>>>>> >>>>>> >>>>>> Can you share a smallish example? >>>>>> My best cold guess would be that Prusaslicer cannot handle the >>>>>> precision of the vertices and ends up merging close vertices causing zero >>>>>> area triangles and it complains. Such repairs are _typically_ benign, >>>>>> unless they cause topology collapse. >>>>>> Bad news is that there is no general solution to fix this; even with >>>>>> a native solution in OpenSCAD, you’d eventually have to make destructive >>>>>> changes to topology if you need to limit vertex precision. >>>>>> >>>>>> -Marius >>>>>> >>>>>> >>>>> >>>> _______________________________________________ >>>> OpenSCAD mailing list >>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>> >>> _______________________________________________ >> OpenSCAD mailing list >> To unsubscribe send an email to discuss-leave@lists.openscad.org >> >