Boolean fuse causes bodies to move

[MikeHersee]

Hi,

I have a problem fusing bodies with Boolean in Parts Design Workbench. Thanks to Bambuko, who created a version for me which I printed, and I found the parameters weren't correct so I went back to my original and adjusted the parameters. Papyblaise had explained you need to fuse only two parts together at a time, so I found that worked. However, back to my original design that I'd adjusted the parameters for and when I tried to fuse two bodies together it has the tendency to move move one of the bodies.

I created a very short video to illustrate the problem: https://youtu.be/DLf_91xbQf4


I found https://forum.freecadweb.org/viewtopic. ... odies+move which was very similar, and the solution to that appeared to be that you have to make sure you select the whole body and not just a sub-component of the body. I only found this after creating the video. However, I've tried various ways of selecting the whole body and I can't seem to work out what to do.

Any help gratefully appreciated as always

Mike Hersee

OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.23756 (Git)
Build type: Release
Branch: master
Hash: 9c6e9184930a52b165a0b7274e3a45d1006bfe67
Python version: 3.8.6
Qt version: 5.12.5
Coin version: 4.0.0
OCC version: 7.4.0
Locale: English/United Kingdom (en_GB)

[openBrain]

Boolean in PartDesign is a bit touchy, but what you have to do is :
* Make the 'master' body active, eg. Body001
* Select other bodies you want to fuse inside Body001
* Run the fuse

Another option is to use Part Workbench and do a 'conventional' fuse between all bodies (in this case, care to select bodies themselves). With this way, all bodies will go in a 'Fusion' object.

[chrisb]

IF you use the PartDesign booleans, the bodies are taken as they are, without their Placement. If you want to fuse these bodies I second Bance's proposal to use the Part boolean Union.

Besides, you don't have to fuse one by one. In some rare cases this helps avoiding other troubles, but usually it works very well.

Finally and most important: You should have modeled all of this in a single body right away. That would probably have worked out of the box, because adding an (additive) feature to a body automatically fuses it with the previous state.

[bambuko]

There is a difference between your original file that you have submitted and I did the boolean for you:

original.jpg (53.35 KiB) Viewed 778 times

and your latest one, where tree looks like this:

latest.jpg (59.2 KiB) Viewed 778 times

and if you are observant you will notice warnings in report view about that.
I bet your problems are caused by you modifying your original file and messing it up in the process

[MikeHersee]

Yes, I can see the differences. I am not sure how they came to be exactly though. I had intended to go back to the original sketches to make adjustments. And I did see the messages, I just wasn't sure what they meant and was in short time to look them up at the time. This is a confusing application at times.

[bambuko]

...This is a confusing application at times.

everything is confusing when you new to it (trust me I was there not so long ago...)
Your best bet is to ditch all the bolean business (there is really no need for it) and follow advice from chrisb earlier on in this thread:

...Finally and most important: You should have modeled all of this in a single body right away. That would probably have worked out of the box, because adding an (additive) feature to a body automatically fuses it with the previous state.

Like so:

vacuum_filter_lock-1body(bambuko).FCStd

(149.7 KiB) Downloaded 20 times

I have used your original design, because second one was beyond redemption,
so you might have to modify some sketch dimensions to get it as you want it...
BTW - none of your sketches were constrained, it was all floating in space etc
Not surprising that boolean was getting confused.
You would do well to read chrisb sketcher lecture (see his signature) before going any further

[MikeHersee]

Thanks for this input. I did manage to get it fused together and printed, and it now means the vacuum cleaner has been in use for the first time for ages.

[MikeHersee]

Thanks for this input. I did manage to get it fused together and printed, and it now means the vacuum cleaner has been in use for the first time for ages.