Assembly3 preview

Discussion about the development of the Assembly workbench.
Mark Szlazak
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Re: Assembly3 preview

Postby Mark Szlazak » Wed Jun 06, 2018 6:30 pm

saso wrote:
Wed Jun 06, 2018 11:35 am
easyw-fc wrote:
Wed Jun 06, 2018 11:23 am
saso wrote:
Wed Jun 06, 2018 10:52 am
this generally works only for more simple Assemblies and in this case then the multi-body structure is used (because bodies go in to Parts).
Body are not present at STEP level at all.
It also does not have a specific Assembly or Part container. In general there is only an hierarchical structure, and it is why it is possible to import it in different ways... Anyway, I have already planed to write a few more things in the "Discussion on Parts and Bodies" topic to hopefully represented my views with a bit more details, so I will do that in the next week or two and we will see then if we can come a bit closer with our views.
Yes please write this up as soon as you able. Thank you!
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easyw-fc
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Re: Assembly3 preview

Postby easyw-fc » Wed Jun 06, 2018 7:26 pm

realthunder wrote:
Wed Jun 06, 2018 7:40 am
Do you notice the different icons DSM used? It is not that hard to guess which icon is for group, which is for object. I'll say that the green icon has no equivalence in FC.
Here a very simple shape I found in the web:
https://github.com/vancegroup-mirrors/s ... e/cube.stp
This is done in SolidWorks

Code: Select all

FILE_NAME ('Cube2.STEP',
    '2010-05-25T09:32:49',
    ( '' ),
    ( '' ),
    'SwSTEP 2.0',
'SolidWorks 2007',
FYI the green icon has the equivalence in FC as a simple 'Part::Feature' geometry.

simple-cube.gif
simple-cube.gif (353.47 KiB) Viewed 589 times
realthunder
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Re: Assembly3 preview

Postby realthunder » Wed Jun 06, 2018 10:38 pm

easyw-fc wrote:
Wed Jun 06, 2018 7:26 pm
FYI the green icon has the equivalence in FC as a simple 'Part::Feature' geometry.
I checked DSM manual. I think the green icon means Solid. And the parent of the green icon, the brownish one is more like FC Part::Compound, or maybe CompSolid, because they have different icon for compound of edges, called Curve. You can try this, import UR10 with upstream, and export it again as STEP. Now open that STEP in DSM, you'll get a different hierarchy. If upstream were to use Part::Compound for those joint, then the round trip will not affect the hierarchy.
Try Assembly3 (latest version 0.10.2) along with my custom build of FreeCAD at here.
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easyw-fc
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Re: Assembly3 preview

Postby easyw-fc » Thu Jun 07, 2018 9:53 am

I also noticed that on this SolidWorks STEP file
https://github.com/vancegroup-mirrors/s ... roduct.stp

I get a different representation of the loaded file in
1) CAD Assistant of OCC and FC 0.17-0.18
cada-fc.png
cada-fc.png (122.79 KiB) Viewed 483 times
2) DesignSpark Mechanical
dsm.png
dsm.png (106.05 KiB) Viewed 483 times
3) FC A3 branch
fc-a3.png
fc-a3.png (88.23 KiB) Viewed 483 times

We definitively need to have someone with access to a commercial CAD like SW, NX, PTC to jump in as tester for STEP In/Out files, otherwise it would be very difficult to tune it without a feedback from what widely used commercial sw do...
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saso
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Re: Assembly3 preview

Postby saso » Thu Jun 07, 2018 10:44 am

It is a multi-body part

like this is sort of ok
Untitled.png
Untitled.png (13.34 KiB) Viewed 465 times

this would be even better
Untitled1.png
Untitled1.png (8.78 KiB) Viewed 465 times

but here we can again hit on about our disagreements about bodies... :roll:

however, as I said before it is possible to import such step files on different levels, above is the example of importing it on the part level (and is correct for this example since it is a multi-body part), but one could also import it on the assembly level, in this case and IF we would have the proper full implementation of the assembly, parts and bodies, then it should be like this (note the assembly container icon on top and the removed origins from the bodies ;) ). This is also how DSM seems to import it (on the assembly level), does DSM support bodies (multi-body)?
Untitled2.png
Untitled2.png (21.29 KiB) Viewed 445 times
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easyw-fc
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Re: Assembly3 preview

Postby easyw-fc » Thu Jun 07, 2018 12:22 pm

saso wrote:
Thu Jun 07, 2018 10:44 am
but here we can again hit on about our disagreements about bodies...
easyw-fc wrote:
Thu Jun 07, 2018 9:53 am
We definitively need to have someone with access to a commercial CAD like SW, NX, PTC to jump in as tester for STEP In/Out files, otherwise it would be very difficult to tune it without a feedback from what widely used commercial sw do...
not only difficult but also useless ...
Moreover we must obtain an exact replica of what is imported, when exported and re-imported.
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nemesis
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Re: Assembly3 preview

Postby nemesis » Thu Jun 07, 2018 7:04 pm

easyw-fc wrote:
Thu Jun 07, 2018 9:53 am
We definitively need to have someone with access to a commercial CAD like SW, NX, PTC to jump in as tester for STEP In/Out files, otherwise it would be very difficult to tune it without a feedback from what widely used commercial sw do...

My 2 cts as I don't really understand all the technical stuf here :D
The file imported with 3DAnalyzer which is only viewer importing a lot of format, and Catia V5R26
CatiaV5R26Import.png
CatiaV5R26Import.png (242.09 KiB) Viewed 368 times

Other maybe "dumb" question, shouldn't we use file from here
I tested one just to see the difference.

StepImport.png
StepImport.png (485.13 KiB) Viewed 368 times
easyw-fc wrote:
Thu Jun 07, 2018 12:22 pm
not only difficult but also useless ...
Moreover we must obtain an exact replica of what is imported, when exported and re-imported.
+1
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easyw-fc
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Re: Assembly3 preview

Postby easyw-fc » Thu Jun 07, 2018 9:26 pm

@nemesis thank you a lot! :D
I was starting with a comparison of very simple STEP files I found on the web made in SolidWorks
nemesis wrote:
Thu Jun 07, 2018 7:04 pm
shouldn't we use file from here
yes please
it would be nice to compare the import of these STEP hierarchical files of the same assembly:
https://www.cax-if.org/library/as1-oc-214.zip (this is generated by OCC kernel)
https://www.cax-if.org/library/as1-pe-203.zip (this is generated by PTC kernel)
https://www.cax-if.org/library/as1-tu-203.zip (this is generated by UG NX kernel)

and
https://www.cax-if.org/library/dm1-oc-214.zip (this is generated by OCC kernel)
https://www.cax-if.org/library/dm1-id-214.zip (this is generated by Siemens PLM Software NX kernel)
https://www.cax-if.org/library/dm1-pe-214.zip (this is generated by PTC kernel)

Thx again,
Maurice
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saso
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Re: Assembly3 preview

Postby saso » Thu Jun 07, 2018 11:36 pm

This is good, but one also has to understand what we are looking at (3DAnalyzer obviously does not support bodies) and understand some of the concepts behind it to understand why both 3DAnalyzer and Catia imported models are actually identical (note that the Geometrical Set.1 in Catia is actually empty, not used). In both cases this are actually just two solids inside a part. And this are also identical to my first and second (part level) imported examples above. And I can tell you that if one knows how to look beyond the differences in the representations of the tree it is all the same in all of the different parametric cad programs.
CatiaV5R26Import.png
CatiaV5R26Import.png (229.08 KiB) Viewed 309 times
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easyw-fc
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Re: Assembly3 preview

Postby easyw-fc » Fri Jun 08, 2018 7:51 am

saso wrote:
Thu Jun 07, 2018 11:36 pm
In both cases this are actually just two solids inside a part.
then the actual importer is doing fine.
And does it sound useful to add a Body container and place a solid inside a Body, considering that FC Body doesn't allow inside a simple Solid?
https://www.freecadweb.org/wiki/PartDesign_Body/en

I think what at the moment is implemented is a good representation of the STEP structure (STEP doesn't have any history of the included shapes).
It can be sure improved, but I think the 'Part' container for the hierarchy is the right one to be used as it is implemented now.