GD&T Workbench for FreeCAD

Here's the place for discussion related to coding in FreeCAD, C++ or Python. Design, interfaces and structures.
Forum rules
Be nice to others! Respect the FreeCAD code of conduct!
User avatar
NewJoker
Veteran
Posts: 3018
Joined: Sun Oct 11, 2020 7:49 pm

Re: GD&T Workbench for FreeCAD

Post by NewJoker »

Pongo wrote: Mon Jul 25, 2022 8:38 am But MBD removes the need for TechDraw, what would need coordinating?
I wouldn't say that MBD removes the need for traditional 2D technical drawings. Those are still very common and useful. MBD is really interesting but not so popular yet. 3D CAD also didn't replace 2D drawings, even though it brought a much larger revolution than MBD.

Regarding cooperation with the TechDraw dev, it could be needed if there was a decision that 2D GD&T capabilities can be realized in form of new tools for the TechDraw workbench. By the way, take a look at the dimensioning capabilities of the Draft workbench. It's the closest to MBD out of what we currently have in FreeCAD.
Jee-Bee
Veteran
Posts: 2566
Joined: Tue Jun 16, 2015 10:32 am
Location: Netherlands

Re: GD&T Workbench for FreeCAD

Post by Jee-Bee »

Personally I'm a fan of MBD and was one of the few using it in my work.
The main reason i did this is track of history. But since not all step versions accept it, a drawing is most of the time required for production. Not talking about the implications of give external parties acces to your files(and track where they have acces to etc).
I think it is more implemented in companies that work in the Hightec branch( like ASML, Philips, etc)...
User avatar
uwestoehr
Veteran
Posts: 4961
Joined: Sun Jan 27, 2019 3:21 am
Location: Germany
Contact:

Re: GD&T Workbench for FreeCAD

Post by uwestoehr »

Pongo wrote: Mon Jul 25, 2022 8:38 am But MBD removes the need for TechDraw, what would need coordinating?
TechDraw is still necessary since in several supply chains you have to specify things as drawing.

For Model-based definition (MDB) you need the same tools TechDraw already has - dimensioning and its editing features. Ideally, FreeCAD works so that the different Workbenches use code from the base classes. So for example you and @wandererfan can work together to outsource the dimensioning to App/Gui of FreeCAD. Then Techdraw and your workbench can use the same code and when there is a bug, we only need to fix it on one position.

Besides this, working together is always a good thing. One can help each other and benefit from the other's experience.
User avatar
Pongo
Posts: 16
Joined: Wed Jul 24, 2019 9:49 am

Re: GD&T Workbench for FreeCAD

Post by Pongo »

uwestoehr wrote: Mon Jul 25, 2022 9:35 pmFor Model-based definition (MDB) you need the same tools TechDraw already has - dimensioning and its editing features. Ideally, FreeCAD works so that the different Workbenches use code from the base classes. So for example you and @wandererfan can work together to outsource the dimensioning to App/Gui of FreeCAD. Then Techdraw and your workbench can use the same code and when there is a bug, we only need to fix it on one position.
Makes sense, I'll move in that direction.
NewJoker wrote: Mon Jul 25, 2022 9:13 amRegarding cooperation with the TechDraw dev, it could be needed if there was a decision that 2D GD&T capabilities can be realized in form of new tools for the TechDraw workbench. By the way, take a look at the dimensioning capabilities of the Draft workbench. It's the closest to MBD out of what we currently have in FreeCAD.
Thanks! I had a look at the Draft workbench and it looks interesting.
Johnny Geling
Posts: 56
Joined: Tue May 26, 2015 9:56 am
Location: Belgium

Re: GD&T Workbench for FreeCAD

Post by Johnny Geling »

Model Based Definition (MDB) and Product Manufacturing Information (PMI) included in the 3D model opens the road to 3D tolerance study / simulation of variation.

For drawing I would suggest to re-use the information from the 3D model.

Johnny
Jee-Bee
Veteran
Posts: 2566
Joined: Tue Jun 16, 2015 10:32 am
Location: Netherlands

Re: GD&T Workbench for FreeCAD

Post by Jee-Bee »

Johnny Geling wrote: Tue Jul 26, 2022 10:12 am For drawing I would suggest to re-use the information from the 3D model.
This suggestion is done before(More than once). It is an easy suggestion but much more difficult to implement.
If you are interested in this you can dive into OCCT documentation.

For me personal I'm already happy if a PD Part(body i know) can have a material assigned to it. And that PD Parts are understood by the FEM WB...
user1234
Veteran
Posts: 3345
Joined: Mon Jul 11, 2016 5:08 pm

Re: GD&T Workbench for FreeCAD

Post by user1234 »

In an ideal world, you make GD&T, dimensions, .... in 3D (in a MDB workbench) and derviate it in 2D (in TechDraw workbench) if someone want.

Greetings
user1234
User avatar
Pongo
Posts: 16
Joined: Wed Jul 24, 2019 9:49 am

Re: GD&T Workbench for FreeCAD

Post by Pongo »

I haven't used FreeCAD much so my experience is quite limited. I should play around with it more, but it would be good to hear more experienced user's opinions also. How does rounding work in FreeCAD? if I specify a dimension e.g. 0.8575, will FreeCAD automatically round this off perhaps under certain conditions? Are there settings that affect this somewhere?

The reason I ask, there can be discrepancies between a CAD model's dimensions and the technical drawing due to the CAD model getting rounded off. This is obviously not very good if I get this MDB Workbench of the ground.
User avatar
wandererfan
Veteran
Posts: 6268
Joined: Tue Nov 06, 2012 5:42 pm
Contact:

Re: GD&T Workbench for FreeCAD

Post by wandererfan »

Pongo wrote: Sun Oct 16, 2022 1:07 pm How does rounding work in FreeCAD? if I specify a dimension e.g. 0.8575, will FreeCAD automatically round this off perhaps under certain conditions? Are there settings that affect this somewhere?

The reason I ask, there can be discrepancies between a CAD model's dimensions and the technical drawing due to the CAD model getting rounded off. This is obviously not very good if I get this MDB Workbench of the ground.
Internally, dimensions values are double precision floating point numbers which have about 15 decimal digits of precision (this varies by platform). For display purposes, dimensions would typically display the number of decimal positions specified by Edit > Preferences > General > Units > Number of decimals.
User avatar
Pongo
Posts: 16
Joined: Wed Jul 24, 2019 9:49 am

Re: GD&T Workbench for FreeCAD

Post by Pongo »

Got you, thank you!
Post Reply