PR#2862: Configuration Table using Spreadsheet

[realthunder]

Why not use a hidden temporary Document to contain the deep copy : with a new hidden temporary document, you are sure that it's empty, thus all copied names will be preserved.? If you copy into the current document, existing names will be changed to keep the unique name principle of FreeCAD, so how do you track the changed (variant) variables ?

Temporary document are not saved, while variant copy is meant to be preserved. The SubShapeBinder supports variant binding as well, and it does indeed use a temporary document for that purpose, because the binder does not need to preserve the variant copies, only the combined shape.

The naming conflict is a common problem that must be solved in order for normal copy to work. You know, when you copy a body and paste it into the same document, FreeCAD must change the reference according to name changes. Similar things happen here. In addition, since this is actually a replace operation, it will also change reference in existing objects. Similar logic has already been implemented in 'Link replace' action in upstream.

Also, is this variant link a C++ construct or a Python object ?

It is implemented in Link using C++.

[Zolko]

It is implemented in Link using C++.

I think that variant links should be implemented in Python, and I have proposed a possible implementation (see here and here). I will (try to) do this now with Assembly4, and for 0.19 if possible

[paullee]

Looks exciting Though probabaly not understanding the usecases.

Can have a simple example, e.g. a Sketch with 4 edges to demonstrate ?

Thanks.

[carlopav]

I think that variant links should be implemented in Python

Can you elaborate?

I will (try to) do this now with Assembly4, and for 0.19 if possible

Sound like duplicated effort... I've tested this PR and "variant subshapebinder" in realthunder fork quite a lot and it works very good in my user opinion...

[galou_breizh]

Thanks realthunder for this nice feature.

I didn't manage to have it work though. I'm attaching a sample where I think I did everything as you wrote but changing the property marked "CopyOnChange" (Pad.Length) still modifies the original object.

copy_on_change.fcstd

(15.45 KiB) Downloaded 130 times

I'm using the AppImage from 2021-09-16 (FreeCAD-asm3-Daily-Conda-Py3-Qt5-20210916-glibc2.12-x86_64.AppImage).

Thanks,
Gaël

OS: Ubuntu 20.04.3 LTS (i3/i3)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 2021.916.24301 +4152 (Git) AppImage
Build type: Release
Branch: LinkDaily
Hash: 7fd36f96f4db17db4f8d058eab22588cca8f9d5c
Python version: 3.9.7
Qt version: 5.12.9
Coin version: 4.0.1
OCC version: 7.5.2
Locale: English/United States (en_US)

[realthunder]

I didn't manage to have it work though. I'm attaching a sample where I think I did everything as you wrote but changing the property marked "CopyOnChange" (Pad.Length) still modifies the original object.

The attached file is broken somehow. I couldn't find the original Body object, and the original Pad is moved outside. Can you please describe your steps? Or maybe make a screencast.

Based on your description, I guess you linked to the body, but mark the Pad.Length as CopyOnCange? The CopyOnChange property only works in the linked object, not any of its sub-objects. You are supposed to create a new property in the linked object, the body, I presume, and then use expression to access the property in various sub-object. To avoid cyclic dependency problem, use 'href()' function. See the screencast below.

phpBB [video]

[galou_breizh]

Thanks for the reply. I got it now.

you linked to the body, but mark the Pad.Length as CopyOnCange? The CopyOnChange property only works in the linked object, not any of its sub-objects.

This is the first thing I was doing wrong. I was indeed setting "Pad.Length" as "CopyOnChange". Here, it should rather "The CopyOnChange property only works at the root of the linked object not in any of its sub-objects or sub-features".

You are supposed to create a new property in the linked object, the body

This is the second thing I was doing wrong (actually I was not doing it and I should have).

It now works wonderfully.

The only thing that could be improved is that it looks that you're doing something that you shouldn't because you need to show things that are normally hidden. I guess the user interface will improve with the time.

Thanks again,
Gaël

[Zolko]

I think that variant links should be implemented in Python

Can you elaborate?

done, works with FreeCAD v0.19:

https://forum.freecadweb.org/viewtopic.php?f=24&t=62558

Anything that can be done in Python should be done in Python. My implementation doesn't need the href() magic that circumvents the real problem of cyclic dependencies. The Part::FeaturePython object takes care of it in its execute() method : it overwrites manu-military its own parameters into the variant (which is a copy of the source object in a hidden temporary document)

There still is an error on restore that I'm not able to intercept, which is scary red but harmless.

[carlopav]

done, works with FreeCAD v0.19:

relevant commit: https://github.com/Zolko-123/FreeCAD_As ... eaef7e99d7

Can you make a screen recording to demonstrate how it works?

PS perhaps in a new topic and linking the new topic here... (?)

[chennes]

I'm working my way through merging this PR, and have just split off a few commits, including the addition of the hidden references, into this "sub-PR" -- https://github.com/FreeCAD/FreeCAD/pull/5151. If anyone interested in hidden references has time to give it a try, I'll leave it a few days for discussion and debugging before merging.