How to use LCS of parts in different sub-sub-assemblies to attach under new assy?

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pio
Posts: 2
Joined: Sun Jan 17, 2021 9:33 am

How to use LCS of parts in different sub-sub-assemblies to attach under new assy?

Post by pio »

Hi everyone,

I am a newbie with FreeCAD, using it a week or so now.
This is my first post and I am not a mechanical engineer, so please excuse
if I still use wrong expressions or are not clear enough (such as the somewhat bulky subject).

My config:
FreeCAD 0.19.23578
Assembly 4 workbench
Windows 10 20H2 64bit

I design a table, assembly "Multifunktionstisch".
It is made up of several sub-assemblies: "TischplatteAssembly" (has a small table plate and a big one), and "TischbeinTopAssembly" (the legs, actually will need 4 of them, each leg has a square tube and the leg top plate).
I created 2 LCS, one on subcomponent "TischplatteKlein" (small table plate), and one on "Deckplatte" (leg top plate).
I want to use those 2 LCS to position the leg to a specific location at the table plate.
See pictures, blue lines for assembly hirarchy, red lines for LCS.

My questions:

1) When I link TischbeinTopAssembly into MultifunktionsTisch, then in the "Place linked part" dialog I see none of the LCS I had defined on sub-component level. I noticed that LCS created on components don't seem to propagate through assembly hirarchies.
Is that on purpose or am I doing something wrong?

2) What is the best way where to define LCS to attach subassemblies to each other? On a component (model, body) that a subassembly is made of?
Or on a higher level (assembly)?

3) Why is LCS_TischbeinVorneRechtsAttach placed directly under element TischplatteKlein, and
LCS_TischplatteAttach is placed under Model under Deckplatte?
I guess I made a mistake in activating the correct element in the first place.
Where should an LCS be placed within a part?

4) If I try to drag the LCS to a different location inside the same assembly element, then it changes the hirarchy of the other
elements (pad, body) depending on from where to where I drag and drop.
I don't understand why.

TargetAssembly.JPG
TargetAssembly.JPG (83.33 KiB) Viewed 236 times
LCS_TischplatteKlein  TischbeinVorneRechts.JPG
LCS_TischplatteKlein TischbeinVorneRechts.JPG (143.05 KiB) Viewed 236 times
LCS _Deckplatte TischplatteAttach.JPG
LCS _Deckplatte TischplatteAttach.JPG (132.91 KiB) Viewed 236 times
Place linked Part dialog.JPG
Place linked Part dialog.JPG (98.85 KiB) Viewed 236 times


Thanks in advance for your patience and support!
Jens
pio
Posts: 2
Joined: Sun Jan 17, 2021 9:33 am

Re: How to use LCS of parts in different sub-sub-assemblies to attach under new assy?

Post by pio »

OK, I need to import the datum (LCS) into the sub assembly from the linked part, before it is selectable by the next higher level assembly.
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