The need for a default assembly workbench

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onekk
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Re: The need for a default assembly workbench

Post by onekk »

Using it as a guideline will not be a good thing?

Maybe adopting a similar terminology too?

NIST has a decent reputation to be trusted for some insight.

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Carlo D.
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wandererfan
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Re: The need for a default assembly workbench

Post by wandererfan »

onekk wrote: Sun Mar 26, 2023 2:27 pm Maybe adopting a similar terminology too?
I'm still working my way through the document, but we might translate a subset of OAM terminology into FreeCAD terminology as:

OAM Artifact = FC Document(?) (Here Artifact is representing Product)
OAM Assembly = FC App::Part
OAM Part = FC PartDesign::Body and Part::Feature(?)
OAM Assembly Feature = FC Constraint(?) and FC LCS(?)

OAM Artifact is a bit of a catch-all. Product, Assembly and Part are all Artifacts. We might call this a base class.

"An Assembly is decomposed into sub-assemblies and parts. A Part is the lowest level component which cannot be further decomposed. The diagram shows that an assembly or a subassembly is made up of at least two parts."

"Assembly feature is defined as an element to specify the relationships between a pair of assembled components. For example, a hole and a cylinder are typical assembly features, which represent the physical connections between a bearing part and a shaft part. The assembly feature association representation is an aggregation of parametric assembly constraints, a kinematic pair, and/or a relative motion between assembly features as shown in Figure 9."
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saso
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Re: The need for a default assembly workbench

Post by saso »

Thanks and yes, this was for a long time my argument and critique on the different assembly wb developments, one has to first establish a clear assembly/part tree structure before doing anything else. Nobody is denying the usefulness or the need of constraints and solvers (more on this in a different post later), I am sure Zolko would also be more then happy to add them to his Asm4, but they by themselves don't give you an assembly. Here is the structure done with just the existing Part containers (so not even using any geometry or LCS or even no Asm4). And all the arguing on solvers, licenses, types of constraints, even comparing of the different Asm WB's are basically meaningless if we don't first understand and agree on this.

AsmNIST.jpg
AsmNIST.jpg (46.65 KiB) Viewed 1106 times

AsmPart.jpg
AsmPart.jpg (25.8 KiB) Viewed 1106 times
Last edited by saso on Tue Mar 28, 2023 11:27 am, edited 6 times in total.
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wandererfan
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Re: The need for a default assembly workbench

Post by wandererfan »

Any default assembly workbench should produce an "output" that is suitable for use in subsequent operations.

Based on limited exposure, Asm4 satisfies this requirement, A2+ may not. I can't speak to Asm3.
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Re: The need for a default assembly workbench

Post by wandererfan »

saso wrote: Sun Mar 26, 2023 3:05 pm one fist has to establish a clear assembly/part tree structure before doing anything else.
That diagram is actually from "the Japanese National Committee (JNC) proposal for a STEP assembly model of products", not the OAM per se, but your point is still absolutely valid.
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Re: The need for a default assembly workbench

Post by saso »

wandererfan wrote: Sun Mar 26, 2023 3:14 pm That diagram is actually from "the Japanese National Committee (JNC) proposal for a STEP assembly model of products", not the OAM per se, but your point is still absolutely valid.
And the important thing to understand here is that this structure by itself should actually be quite simple and in a way rigid, because it is then very easy to build BOMs from it and do proper STEP imports/exports of assemblies.
Last edited by saso on Tue Mar 28, 2023 11:30 am, edited 2 times in total.
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Re: The need for a default assembly workbench

Post by saso »

adrianinsaval wrote: Sat Mar 25, 2023 5:04 pm If I'm not mistaken this isn't necessary for bodies as they will have the same structure as a Part when exported, right?
Much has been said about this already in the past, and I would not want to start this debate again in this topic, but basically the implementation of Bodies in FC is just wrong (at least that is my view). They act as both a body and a part at the same time and this is just wrong and bad.
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Re: The need for a default assembly workbench

Post by adrianinsaval »

DISCLAIMER: I have not read the document, my opinions are based solely on what has been said in this thread and my previous knowledge of other CAD systems.
wandererfan wrote: Sun Mar 26, 2023 3:00 pm OAM Part = FC PartDesign::Body and Part::Feature(?)
I'm not sure fi this is correct, from what I understood earlier I think it's not desired to have standalone Part::Feature objects directly under the assembly container, so instead this would be App:Part too.
OAM Assembly Feature = FC Constraint(?) and FC LCS(?)
I think it means much more than that, in other CAD systems you do some operations in the assembly, like mirroring, pocketing and can't remember what else. I think this has been mentioned before here too.
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FBXL5
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Re: The need for a default assembly workbench

Post by FBXL5 »

wandererfan wrote: Sun Mar 26, 2023 3:07 pm Based on limited exposure, Asm4 satisfies this requirement, A2+ may not. I can't speak to Asm3.
ASM3 can handle assemblies and subassemblies as well, but uses its own Assembly container instead of the FC App::Part.
It works well with App::Links and PD bodies at least.
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