Looking for 1st geometric parent of an object

[Roy_043]

What is the 'standard' way to look for the 1st geometric parent of an object. By geometric parent I mean a parent with a coordinate system:

Code: Select all

Part
    Group
    Group001
        Part001
            Wire
            Part002
                Group002
                    Wire001

For Wire001 it is Part002. For Wire it is Part001.

I can come up with the function below.
But I do not know how reliable this is. When would the Parents method return a list with more than one item?
The solution is also a bit convoluted, the return value of the Parents method is not ideal for this purpose.

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def object_get_parent (obj):
    parents = obj.Parents
    if parents:
        lst = [parents[0][0].Name] + parents[0][1].split(".")
        if len(lst) > 2:
            return obj.Document.getObject(lst[len(lst)-3])
        return None
    return None

[Pauvres_honteux]

Could this, by any chance, have anything in common with Children and/or parent to be highlighted when hoovering over something in the tree/3D viewport ?

[Roy_043]

No, your FR is unrelated. But I suppose you already knew this.

[onekk]

It is not possible to inspect the tree?

As usual the problem could be the ".Name" versus ".Label" difference present in FreeCAD.

But once obtained the Object (TreeView show the Label property if I don't go wrong) the Name could be obtained rather easily.

Regards

Carlo D.

[Roy_043]

It is not possible to inspect the tree?

The Parents property is giving the required result, it is just that the implementation is rather awkward.

[onekk]

Sorry I could not find a way to use your code.

Could you kindly make a simple working example?

You have made me very curious about the problem, and surely it will be a learning experience.

Only if this could not cause you too much trouble, obviously.


TIA and Regards

Carlo D.

[Roy_043]

Code: Select all

>>> wr0 = App.ActiveDocument.Wire
>>> wr1 = App.ActiveDocument.Wire001
>>> object_get_parent(wr0).Label
'Part001'
>>> object_get_parent(wr1).Label
'Part002'

IMO the Parents property has a strange format:

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>>> wr1.Parents
[(<Part object>, 'Part001.Part002.Wire001.')]

Why is there a tuple inside a list? Why return the top-parent as an object, and the rest as names in a string that needs to be split to be useful. And why add the object itself to that string? And why does the string end in "."? Unless I am missing something, and that may very well be the case, this seems very inconvenient.

[carlopav]

Could maybe be because an object can appear 2 Times in 2 different positions since link implementation?
Ex:

Code: Select all

Part001-Part002-Wire001
LinkToPart001-Part002-Wire001

[Roy_043]

Ah yes, you are right.

Code: Select all

>>> wr1 = App.ActiveDocument.Wire001
>>> wr1.Parents
[(<App::Link object>, 'Part002.Wire001.'), (<Part object>, 'Part001.Part002.Wire001.')]

Note that the getGlobalPlacement() method does not take this possibility (Wire001 has two geometric parents, and appears in two places in the GCS) into account.

[onekk]

Why is there a tuple inside a list? Why return the top-parent as an object, and the rest as names in a string that needs to be split to be useful. And why add the object itself to that string? And why does the string end in "."? Unless I am missing something, and that may very well be the case, this seems very inconvenient.

From a programmers point of view tuple is very handy, as it is immutable and use less memory.

The trailing dot maybe is simply a consequences of the name composition methods, if you append a dot, and add something after you have not to take in account to check if the dot exist or not, plus the .split() function will return an empty string or nothing that could be parsed with a simple if statement.

For the two objects parents, I think that the method is returning the tree in a schematic way, the string has to be parsed maybe to obtain proper "Names" without retrieving the object itself and checking for his "Name" property .

It will be interesting to see how in the existing code the property is used, maybe a grep in the source tree will be interesting, or maybe some comments in the code will bring some light on the matter. Let me see.

Edit I: I've seen a similar writing somewhere in "programmin world", but now I don't rembember where.

EDIT II: Sorry no results, using Parents or .Parents in a grep -nR over the source tree of the 0.19 that I have handy on the computer.

I've searched the item on the /Mod/. tree, so maybe it is in the C++ section, or is derived from somewhere else, like an external library, I've searched also in Qt (using the Web Qt search field on Qt official pages but no luck)

Regards

Carlo D.