PR #4074 The section cut feature

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uwestoehr
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Re: PR #4074 The section cut feature

Postby uwestoehr » Mon Apr 05, 2021 11:31 pm

M4x wrote: Sun Apr 04, 2021 1:45 pm Does more work has to go into this or is this already something that could be merged during the 0.20 dev cycle?
It could be merged, or It can become a separate Workbench. It depends on the people who merge. The issue is that a real cut consumes a lot of calculations. So for a simple assembly of e.g. just 4 parts, there is no big issue, but for a 20 part assembly you can go drink a coffee before you see the first cut. (depending in the complexity of the parts of course).

But OK, we should nevertheless offer this feature and just inform the users that it can be time-consuming to get the cut one wants.
Personally I already used this feature because I had to explain colleagues what I designed and why.

Do you need this feature soon? If so, I'll try to rebase the PR and have a look what needs to be done.
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M4x
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Re: PR #4074 The section cut feature

Postby M4x » Mon Apr 26, 2021 9:01 pm

Thank you very much for your fast reply (and sorry it took me so long to reply again :roll: ). I can survive without it, but it would be really handy right now.
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Zolko
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Re: PR #4074 The section cut feature

Postby Zolko » Tue Apr 27, 2021 6:19 am

M4x wrote: Sun Apr 04, 2021 1:45 pm Does more work has to go into this or is this already something that could be merged during the 0.20 dev cycle?
please merge this for v0.20, this is a fundamental tool for complex assemblies

uwestoehr wrote: Mon Apr 05, 2021 11:31 pm The issue is that a real cut consumes a lot of calculations. So for a simple assembly of e.g. just 4 parts, there is no big issue, but for a 20 part assembly you can go drink a coffee before you see the first cut. (depending in the complexity of the parts of course).
did you try to combine this with the clipping tool ? That one is very fast, but produces hollow objects (which is understandable, since the B in BREP stands for Boundary Representation). In an ideal world, one could use the clipping tool for preview and adjust the settings, and when accepted apply the section tool.

Heck, this could be a good subject for the GSoC
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uwestoehr
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Re: PR #4074 The section cut feature

Postby uwestoehr » Fri May 14, 2021 10:07 pm

Zolko wrote: Tue Apr 27, 2021 6:19 am please merge this for v0.20, this is a fundamental tool for complex assemblies
OK, I'll try to work on this to make it ready.
did you try to combine this with the clipping tool ?
This was my start. But since the hollow results are quite unusable in practice, I saw that a real cut is necessary. @wmayer also reviewed the PR and tried to find a quicker solution. It seems there is no one yet.
Meanwhile I realized that the sliders are unnecessary, they lead to the many calculations. A stepwise change of the cut positions should be sufficient. Nevertheless, I don't understand why just one simple cut takes so long. With OCC .7.4 they improved the cutting speed by almost 100 % as I measured, so there is obviously something in the OCC kernel that can still be improved since in Solidworks and friends the cutting does not take minutes.
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Re: PR #4074 The section cut feature

Postby carlopav » Sun May 30, 2021 12:59 pm

realthunder wrote: ping
uwestoehr wrote: Fri May 14, 2021 10:07 pm This was my start. But since the hollow results are quite unusable in practice, I saw that a real cut is necessary. @wmayer also reviewed the PR and tried to find a quicker solution. It seems there is no one yet.
Looks like @realthunder did it again! :shock:

here attached a screenshot from the fb page of OfficineRobotica:

section fill.jpg
section fill.jpg (208.68 KiB) Viewed 739 times
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Re: PR #4074 The section cut feature

Postby OficineRobotica » Sun May 30, 2021 1:52 pm

carlopav wrote: Sun May 30, 2021 12:59 pm

Looks like @realthunder did it again! :shock:

here attached a screenshot from the fb page of OfficineRobotica:
The feature was announced in the release notes of Realthunder's latest daily. The "problem"(sort of speak) is that the cross section filling uses the new experimental renderer present in LinkStage3 to fill the hollow geometry of the bodies. From my personal experience this is the first new trick that the new renderer enables other than having BIG performance gains as fps. From the fosdem talk we know that he plans to build allot more on top of this renderer .It is awesome tough to have it and I totally agree with Zolko. This is really needed for assemblies.

From my programming ignorant point of view the real problem tough is the need to merge all these awesome features. And I'm Realthunder's biggest fan as the rest of us but believe me that LinkStage3 is packed full with improvements like this.
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M4x
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Re: PR #4074 The section cut feature

Postby M4x » Sun May 30, 2021 4:21 pm

Just to be clear, maybe we're talking about different usecases. The current clipping functionality is something visual. This goes for realthunders improvement too. If you only want to show something, realthunders implementation looks awesome. But are you able to measure something in the region of the cut? I assume not. Therefore a "real" cut functionality would be great.
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Re: PR #4074 The section cut feature

Postby uwestoehr » Mon Jun 07, 2021 12:20 am

M4x wrote: Sun May 30, 2021 4:21 pm Just to be clear, maybe we're talking about different usecases. ...Therefore a "real" cut functionality would be great.
Exactly. The use use case I had and have is to heave real cuts, meaning you can use the cross section as normal object. Not only to measure things out, but to use it in assemblies and for animations. In my case I even printed the section cut using a 3D-printer and used this as demonstrator at a fair.

As soon as I find time, I will update the PR to get it merged soon.
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Re: PR #4074 The section cut feature

Postby uwestoehr » Mon Jun 07, 2021 12:22 am

Inviting realthunder to hear his opinion.
realthunder wrote: .
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Re: PR #4074 The section cut feature

Postby realthunder » Mon Jun 07, 2021 11:28 pm

uwestoehr wrote: Mon Jun 07, 2021 12:22 am Inviting realthunder to hear his opinion.
Yes, a real section operation is certainly useful in many cases. I have added a 'Wrap' feature in my branch for adding almost any non PartDesign feature to a body, which is one way of using it, but of course a native section feature will be more convenient.
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