Re: STL best practices & tools
Do you have the lazy union option enabled? If so you need to explicitly
union the top level object before exporting to STL.
On Wed, 7 Jun 2023, 18:05 neri-engineering via Discuss, <
discuss@lists.openscad.org> wrote:
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From: neri-engineering neri-engineering@protonmail.com
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Date: Wed, 07 Jun 2023 17:04:11 +0000
Subject: [OpenSCAD] Re: STL best practices & tools
Thanks, I did find a Youtube video as well on AngelCAD:
https://www.youtube.com/watch?v=h-qDzG9bwnQ
I downloaded your source code and have it on my filesystem. I see it's
C++. Great. I found the source code for polyfix, it's quite short, but
may be using some other libs that you wrote.
Are there any tips/docs on how to use polyfix. In the short term I want
to pass in a single STL file and have it reconcile faces that are coplanar
and overlapping by area, facing in opposite directions (relative to
"outside"). This operation could be done on a single connected polyhedron
which has "spikes" that touch or very nearly touch, as well. I presume
that an epsilon value is being used; I saw something in the source code.
Meanwhile I'm doing more independent investigation into what's going on
behind the scenes in OpenSCAD, and why some simple cases are creating
polyhedron that won't union()ize inside the STL. I suspect that one of the
problems might possibly be that a conversion from 64 bit float to 32 bit
float is happening too soon. I know from the STL spec that coordinates
specified in STL are 32 bit float (from the best of my recollection - but I
could check this again).
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------- Original Message -------
On Saturday, June 3rd, 2023 at 11:40 PM, Carsten Arnholm <
arnholm@arnholm.org> wrote:
I imagine using an approach similar to that of my near-perfect retro
line-drawing algorithm,
in order to implement an STL cleanup tool which combines STL pieces
that "touch" into one solid
object. ("Touch" within an epsilon value which is configurable.)
Hi, I wrote such a tool. It is called 'polyfix' and it is part of the
AngelCAD suite
https://github.com/arnholm/angelcad/releases/tag/V1.5-06
Regards
Carsten Arnholm
P.S: Good decision on the 'jab'. It is a crime against humanity
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Date: Wed, 07 Jun 2023 17:04:11 +0000
Subject: [OpenSCAD] Re: STL best practices & tools
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Short answer: I don't think I have "lazy union" enabled. I was not even aware of this feature. I did not find anything mentioning this feature in the GUI, under Preferences.
I did find this on the internet (see image attached).
[lazy-unions.png]
So, short answer, "no, I don't have lazy unions enabled".
More definite answer, and additional information, shortly. I'm trying to come up with a small code sample (making it as simple and as small as possible) that demonstrates the issue that I am having.
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------- Original Message -------
On Wednesday, June 7th, 2023 at 12:13 PM, nop head nop.head@gmail.com wrote:
Do you have the lazy union option enabled? If so you need to explicitly union the top level object before exporting to STL.
On Wed, 7 Jun 2023, 18:05 neri-engineering via Discuss, discuss@lists.openscad.org wrote:
---------- Forwarded message ----------
From: neri-engineering neri-engineering@protonmail.com
To: OpenSCAD general discussion Mailing-list discuss@lists.openscad.org
Cc:
Bcc:
Date: Wed, 07 Jun 2023 17:04:11 +0000
Subject: [OpenSCAD] Re: STL best practices & tools
Thanks, I did find a Youtube video as well on AngelCAD: https://www.youtube.com/watch?v=h-qDzG9bwnQ
I downloaded your source code and have it on my filesystem. I see it's C++. Great. I found the source code for polyfix, it's quite short, but may be using some other libs that you wrote.
Are there any tips/docs on how to use polyfix. In the short term I want to pass in a single STL file and have it reconcile faces that are coplanar and overlapping by area, facing in opposite directions (relative to "outside"). This operation could be done on a single connected polyhedron which has "spikes" that touch or very nearly touch, as well. I presume that an epsilon value is being used; I saw something in the source code.
Meanwhile I'm doing more independent investigation into what's going on behind the scenes in OpenSCAD, and why some simple cases are creating polyhedron that won't union()ize inside the STL. I suspect that one of the problems might possibly be that a conversion from 64 bit float to 32 bit float is happening too soon. I know from the STL spec that coordinates specified in STL are 32 bit float (from the best of my recollection - but I could check this again).
Sent with Proton Mail secure email.
------- Original Message -------
On Saturday, June 3rd, 2023 at 11:40 PM, Carsten Arnholm arnholm@arnholm.org wrote:
I imagine using an approach similar to that of my near-perfect retro
line-drawing algorithm,
in order to implement an STL cleanup tool which combines STL pieces
that "touch" into one solid
object. ("Touch" within an epsilon value which is configurable.)
Hi, I wrote such a tool. It is called 'polyfix' and it is part of the
AngelCAD suite
https://github.com/arnholm/angelcad/releases/tag/V1.5-06
Regards
Carsten Arnholm
P.S: Good decision on the 'jab'. It is a crime against humanity
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
---------- Forwarded message ----------
From: neri-engineering via Discuss discuss@lists.openscad.org
To: OpenSCAD general discussion Mailing-list discuss@lists.openscad.org
Cc: neri-engineering neri-engineering@protonmail.com
Bcc:
Date: Wed, 07 Jun 2023 17:04:11 +0000
Subject: [OpenSCAD] Re: STL best practices & tools
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