Union of three bodies fails

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JiPe38
Posts: 123
Joined: Wed Jan 01, 2020 12:41 pm

Union of three bodies fails

Postby JiPe38 » Fri Jan 24, 2020 12:45 pm

Hi everyone
I tried to make an union of three bodies. One central is a clone of a model cube, the two others are clones of a model half cylindre.
I create my three clones, add a translation on x on the first half cylindre, a rotation around y and an opposed translation on x on the second half cylindre. I see correctly my three bodies, joined in the final position that I want. I then ask the creation of a new body, with a boolean union function, select the three clones... up to there everything is smooth and OK. Then I click on the "OK" button of the boolean union and, upon it's exit, I see only the last two selected bodies of the union.
Do I miss something, or is there a known problem in such an operation ?
threeBodyUnion.FCStd
(26.51 KiB) Downloaded 9 times
OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.19311 (Git)
Build type: Release
Branch: master
Hash: 120b69c74f7dac8c4fa6dbc0a7e10674bde9216c
Python version: 3.7.3
Qt version: 5.12.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: French/France (fr_FR)
chrisb
Posts: 22455
Joined: Tue Mar 17, 2015 9:14 am

Re: Union of three bodies fails

Postby chrisb » Fri Jan 24, 2020 1:59 pm

A boolean in a PartDesign body is different from a boolean in Part: Like all other features it adds/subtracts from the solid created so far. As you don't have a solid if the boolean is the first item in the body, fancy things can happen.
PartDesign Booleans are not really a replacement for Part Booleans. If you want those, take them from Part workbench.

In your case you should simply model it all in one body.
openBrain
Posts: 3406
Joined: Fri Nov 09, 2018 5:38 pm

Re: Union of three bodies fails

Postby openBrain » Fri Jan 24, 2020 2:03 pm

IIRC it has already been reported that Union bugs with 3 objects. I'll try to find a link.
JiPe38
Posts: 123
Joined: Wed Jan 01, 2020 12:41 pm

Re: Union of three bodies fails

Postby JiPe38 » Fri Jan 24, 2020 2:06 pm

chrisb wrote:
Fri Jan 24, 2020 1:59 pm
A boolean in a PartDesign body is different from a boolean in Part: Like all other features it adds/subtracts from the solid created so far. As you don't have a solid if the boolean is the first item in the body, fancy things can happen.
PartDesign Booleans are not really a replacement for Part Booleans. If you want those, take them from Part workbench.

In your case you should simply model it all in one body.
What I present in this simple example is a simplification of a complex model, reduced to show where the problem arises. I can't design this in just one body.
chrisb
Posts: 22455
Joined: Tue Mar 17, 2015 9:14 am

Re: Union of three bodies fails

Postby chrisb » Fri Jan 24, 2020 2:15 pm

JiPe38 wrote:
Fri Jan 24, 2020 2:06 pm
What I present in this simple example is a simplification of a complex model, reduced to show where the problem arises. I can't design this in just one body.
But you can always use bodies which do not start with a boolean.
openBrain
Posts: 3406
Joined: Fri Nov 09, 2018 5:38 pm

Re: Union of three bodies fails

Postby openBrain » Fri Jan 24, 2020 2:24 pm

Was in your mother language JiPe38 : https://forum.freecadweb.org/viewtopic. ... 20#p358024 :)
But I guess this deserves a dedicated discussion. So let's go for it. I'll confirm later when I have a PC if nobody did in between.
A minimalist example would also be welcome. ;)
Roy_043
Posts: 887
Joined: Thu Dec 27, 2018 12:28 pm

Re: Union of three bodies fails

Postby Roy_043 » Fri Jan 24, 2020 7:11 pm

openBrain
Posts: 3406
Joined: Fri Nov 09, 2018 5:38 pm

Re: Union of three bodies fails

Postby openBrain » Fri Jan 24, 2020 8:05 pm

Roy_043 wrote:
Fri Jan 24, 2020 7:11 pm
This discussion?:
https://forum.freecadweb.org/viewtopic.php?f=8&t=41910
Not a lot to do with current discussion. ;) The one you pointed talks about boolean operations of PartDesign. ;)
chrisb
Posts: 22455
Joined: Tue Mar 17, 2015 9:14 am

Re: Union of three bodies fails

Postby chrisb » Fri Jan 24, 2020 9:00 pm

openBrain wrote:
Fri Jan 24, 2020 8:05 pm
The one you pointed talks about boolean operations of PartDesign. ;)
That's exactly what OP talks about:
JiPe38 wrote:
Fri Jan 24, 2020 12:45 pm
I then ask the creation of a new body, with a boolean union function,
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GlouGlou
Posts: 2009
Joined: Sun Apr 05, 2015 9:02 am
Location: La Rochelle, France

Re: Union of three bodies fails

Postby GlouGlou » Fri Jan 24, 2020 9:41 pm

with partdesign the worflow is different of part.
active one body, then call the boolean feature then select the other bodies.
theses two bodies will embedded inside the first one.
Attachments
threeBodyUnion.FCStd
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