Assembly3, A2plus, Assembly4? Get united!

Discussion about the development of the Assembly workbench.
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godblessfq
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Re: Assembly3, A2plus, Assembly4? Get united!

Post by godblessfq »

drmacro wrote: Sun Oct 17, 2021 1:01 pm
godblessfq wrote: Sun Oct 17, 2021 12:35 pm I've heard Assembly 4 doesn't have topological naming issue. But these LCSs actually needs something to attach to, what if one of these attachment is changed or deleted?
[qutoe]
Can you provide a reference to this "heard" discussion?
You can have a simple example of put a lcs on the cylinder edge of a chamfer, later delete the chamfer, your assembly is broken.
I have created an issue on the assembly 4 repo.
https://github.com/Zolko-123/FreeCAD_As ... issues/265
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Zolko
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Re: Assembly3, A2plus, Assembly4? Get united!

Post by Zolko »

drmacro wrote: Sun Oct 17, 2021 1:01 pm
godblessfq wrote: Sun Oct 17, 2021 12:35 pm I've heard Assembly 4 doesn't have topological naming issue.
Can you provide a reference to this "heard" discussion?
he might be referring to what I said in another thread. Actually, Assembly4 is immune to the TNP only if one constructs the assembly using master sketches and datums. You define first the attachment points, determined by the function of the part, and then design the geometry around that. Which is what you do anyway implicitly, but with Asm4 it's explicit.

godblessfq wrote: Sun Oct 17, 2021 12:35 pm But these LCSs actually needs something to attach to, what if one of these attachment is changed or deleted?
Ideally, you shouldn't attach datums to geometry, but to other datums (with offsets) and to sketches (also called "master sketches").

godblessfq wrote: Sun Oct 17, 2021 12:35 pm Otherwise, I don't think we need all those extra LCSs, because all thoses LCSs are just duplicate of the information contained in the shape.
and yet, they exist in all major CAD systems : did you ever wonder why ?
try the Assembly4 workbench for FreCAD — tutorials here and here
drmacro
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Re: Assembly3, A2plus, Assembly4? Get united!

Post by drmacro »

Zolko wrote: Sun Oct 17, 2021 5:59 pm ...
and yet, they exist in all major CAD systems : did you ever wonder why ?
BTW, my reference to RGB porcupines is meant to be a joke. 8-)

I'm well aware of how to hide them when desired. ;)
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."
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