[Workaround Found] Holes turning square in Assembly4 mirrored parts?

[itsgc]

Hello folks!

first time poster and fairly new Freecad user. I have an odd issue that i have been unable to work around in a meaningful manner. Hope the level of detail is enough but if not apologies and i'll do my best to fill in the gaps.

What i am trying to do
Create mirrored side panels of a woodworking cabinet with matching screw holes.

Install Details
I have Freecad 0.19 installed via the Ubuntu PPA on Launchpad: https://launchpad.net/~freecad-maintain ... cad-stable

OS: Ubuntu 20.04.3 LTS (ubuntu:GNOME/ubuntu)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.
Build type: Release
Branch: unknown
Hash: 0d9536ed3e8c7f40197b5606e1b7873625e1d6fe
Python version: 3.8.10
Qt version: 5.12.8
Coin version: 4.0.0
OCC version: 7.5.2
Locale: English/United Kingdom (en_GB)

Assembly4 Version: v0.11.5


Situation
I am working on a set of parts with Assembly4 and Part Design. The part is (to me) relatively simple, a padded rectangular sketch with 3 holes in it added after padding. The "part" and body components are created in Assembly4. I switch to Part Design once the body is created to sketch out the Rectangular part and 3 holes on its left-most face.

After that i switch back to Assembly4 and i use "Create a mirrored part of a part" using the Y-Z axis to create a right-hand version of the same part.

Problem
The 3 holes in the mirrored part turn square, but only if an LCS component is present in the parent part. I'd like them to stay round as they are meant to be through holes for the shoulder on confirmat screws.

Troubleshooting steps attempted
- Removing the LCS from the parent part turns the holes round again
- Removing the LCS from the mirrored part does nothing (if the parent LCS is still there)
- Using other kinds of "Datum Objects" does not make the holes square. I tried both a point and an axis
- Placement and type of the parent LCS is irrelevant. It can be "deactivated", or "Translate origin" or "Inertial CS" and will still make the holes square.
- Tried version "0.20~pre1~202201050418~ubuntu20.04.1" from the freecad-daily PPA, no change! Same exact behavior.

I am not quite sure what i am doing wrong to cause this but having a look at the wiki and the forum did not really yield anybody running into the same issue, at least searching for terms such as "assembly4 mirror square holes" and "mirrored holes square" etc.

Attachments

SquareHoleTest.FCStd

FreeCAD file exhibiting the issue

(24.97 KiB) Downloaded 20 times

Here are a couple of screenshots of the problem:

Round Hole in parent part

Screenshot from 2022-01-05 16-16-50.png (245.27 KiB) Viewed 1468 times

Square Hole in mirrored part

Screenshot from 2022-01-05 16-17-30.png (254.61 KiB) Viewed 1468 times

And here is a screen-cast of the change in behavior happening when removing the LCS from a parent part:
- External MP4 Link (IMGUR): https://imgur.com/PqVF76M
- WebM attached to Post

square_holes.webm

Screencast showcasing the issue.

(907 KiB) Downloaded 19 times

Any help would be appreciated! Thank you

[chrisb]

Hi and welcome to the forum!

Good first post with FreeCAD infos, file, images, even a video. I'm sorry that I cannot help, as I'm not familiar with assemblies. I move the topic to Assembly forum.

[itsgc]

Hi and welcome to the forum!

Good first post with FreeCAD infos, file, images, even a video. I'm sorry that I cannot help, as I'm not familiar with assemblies. I move the topic to Assembly forum.

No worries and thanks for the welcome! Hopefully someone has ran into this ahah.

[itsgc]

Hello,
maybe this is a bug in "Create symmetric of part":

Pockets based on sketched circels became quads in the mirrored part (?).

mirrored part.png

Code: Select all

FreeCAD Assembly 4 workbench
Current version 0.11.5

OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.20.25645 (Git)
Build type: Release
Branch: master
Hash: 37d9757399b4c2ec30318eb88d7cd7c508246345
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.0
Locale: German/Germany (de_DE)

Oh actually looks like i'm not the only one with this issue User "Freecutter" ran into this as well, and looks like Assembly4's developer sort of acknolwedged this might be a bug in a post further down.

[itsgc]

Just to follow up on my own topic, i was able to work-around this issue by using the Part workbench. It has a "Mirror" part feature very similar to Assembly4's but seems unaffected by the square holes bug. It is a bit more finicky to use and unfortunately the mirrored copies will be independent of each other once created but it'll get the job done.

What i did was:
In Assembly4
Create a new empty part that will contain the mirrored body

Screenshot from 2022-01-06 15-53-13.png (38.75 KiB) Viewed 1249 times

Right-click "copy" on the original body, a prompt will ask you which sub-components to copy. I left the default selection of all elements.

Screenshot from 2022-01-06 15-53-27.png (169.7 KiB) Viewed 1249 times

Screenshot from 2022-01-06 15-53-44.png (92.02 KiB) Viewed 1249 times

Paste inside the new part container and a new body will be created, identical (not mirrored) to the original

Screenshot from 2022-01-06 15-54-04.png (161.83 KiB) Viewed 1249 times

Sometimes the copy will be pasted outside the part container, move it inside.

Screenshot from 2022-01-06 15-54-55.png (28.26 KiB) Viewed 1249 times

Continued in post below.

[itsgc]

Switch to Part Workbench
Select the copied body and click "Mirroring a selected shape"

Screenshot from 2022-01-06 15-55-47.png (145.29 KiB) Viewed 1244 times

Choose an appropriate mirror plane. For front-facing parts that you want to mirror left-to-right i use Y-Z but there are only 3 options so with a bit of experimentation you should get the part you want.

Screenshot from 2022-01-06 15-56-10.png (54.42 KiB) Viewed 1244 times

A new mirrored component will appear *outside* the part container you created in step 1.

Screenshot from 2022-01-06 15-56-25.png (45.88 KiB) Viewed 1244 times

Move the mirror inside the Part container and the original non-mirrored copy should get nested inside it.

Screenshot from 2022-01-06 15-56-54.png (47.07 KiB) Viewed 1244 times

Hide the non-mirrored child component and you should end-up with only a mirrored part visible.

Screenshot from 2022-01-06 15-57-16.png (44.27 KiB) Viewed 1244 times

Hope this helps! Looking forward to the actual Assembly mirror functionality to work as intended but in the mean-time this will do for me.