Assembly3 attaching with multiple holes

Discussion about the development of the Assembly workbench.
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DaAwesomeP
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Assembly3 attaching with multiple holes

Postby DaAwesomeP » Wed Jun 09, 2021 5:13 pm

Hello!

I am attempting to attach some parts to a grid of holes.

For the longer flat piece, I am able to do two AxialAlignments, but then a PlaneAlignment after that does not work. For the other pieces, I cannot do the two AxialAlignments. The Attach constrain does not align them properly.

How should I constrain them together?
attach.png
attach.png (153.85 KiB) Viewed 461 times
File was too large to attach: https://drive.google.com/file/d/1bKerxE ... sp=sharing

Thanks!

OS: Windows 10 Version 2009
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 2021.528.24301 +3572 (Git)
Build type: Release
Branch: LinkStage3
Hash: 1578dc89cb181b96e75d9fb128d82b0ec1460291
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.0
Locale: English/United States (en_US)
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jpg87
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Re: Assembly3 attaching with multiple holes

Postby jpg87 » Wed Jun 09, 2021 7:52 pm

DaAwesomeP wrote: Wed Jun 09, 2021 5:13 pm For the longer flat piece, I am able to do two AxialAlignments, but then a PlaneAlignment after that does not work. For the other pieces, I cannot do the two AxialAlignments. The Attach constrain does not align them properly.
Hello,
If I answer your question strictly, you must put the constraints that remove the desired DOFs with the minimum of redundancy.
For example instead of 2 AxialAlignment (which leave an axial displacement but with an over-constrained positioning), use a PlaneCoincident between 2 circles, then a SameOrientation between 2 edges which must remain parallel.

If you don't have a lot of experience with Assembly 3 and given the size of your project, I think you need to be more rigorous although it might seem overwhelming.

I suggest you visit my website http://help-freecad-jpg87.fr/02_ass_ind.php

Then if you have any problems, I can help you.
My website : http://help-freecad-jpg87.fr updated 2021/05/27
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DaAwesomeP
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Re: Assembly3 attaching with multiple holes

Postby DaAwesomeP » Thu Jun 10, 2021 2:22 pm

jpg87 wrote: Wed Jun 09, 2021 7:52 pm For example instead of 2 AxialAlignment (which leave an axial displacement but with an over-constrained positioning), use a PlaneCoincident between 2 circles, then a SameOrientation between 2 edges which must remain parallel.
I tried that and the PlaneCoincident and SameOrientation work independently, but in combination I get an "inconsistent constraints" message and they do not align.

jpg87 wrote: Wed Jun 09, 2021 7:52 pm If you don't have a lot of experience with Assembly 3 and given the size of your project, I think you need to be more rigorous although it might seem overwhelming.

I suggest you visit my website http://help-freecad-jpg87.fr/02_ass_ind.php

Then if you have any problems, I can help you.
I will be sure to check it out now, thank you!
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jpg87
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Re: Assembly3 attaching with multiple holes

Postby jpg87 » Sat Jun 12, 2021 10:39 am

DaAwesomeP wrote: Thu Jun 10, 2021 2:22 pm I tried that and the PlaneCoincident and SameOrientation work independently, but in combination I get an "inconsistent constraints" message and they do not align.
Hello,
I tested on my end and I have the same problem which did not occur before. I used another approach and got this :

Asm3Rover.png
Asm3Rover.png (74.8 KiB) Viewed 245 times

If this is what you are looking for, I will make my file available and give you all the explanations you want.
My website : http://help-freecad-jpg87.fr updated 2021/05/27
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jpg87
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Re: Assembly3 attaching with multiple holes

Postby jpg87 » Mon Jun 14, 2021 12:43 pm

DaAwesomeP wrote: Thu Jun 10, 2021 2:22 pm SameOrientation
After an exchange with Realthunder, I noticed that the SameOrientation constraint prohibited all rotations between the two constrained objects (3 DOFs remaining), whereas I mistakenly believed that only the normals were made parallel. On the other hand, the MultiParallel constraint renders well (and only) the normals to the designated planes (4 DOFs remaining).

And yet that doesn't seem to work either!

While waiting for Realthunder's response, I had used the Perpendicular constraint between two judiciously chosen surfaces, so I am forced to stay on this constraint for now.
My website : http://help-freecad-jpg87.fr updated 2021/05/27