Applyed GA for mechanical assembly

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etm...@gmail.com

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Mar 2, 2018, 11:57:09 AM3/2/18
to Geometric_Algebra
I am designing 3d parts using the freecad system, for educational purposes. 
There are approximately 1000 assemblies used in electrification that have a pole and associated parts like belt, saddle, crosshead, top pin, insulator. 
In the figure below we see an assembly where the pieces were drawn separately with the same Cartesian reference 0,0,0. 
The pieces were grouped using a python script and then manually moved to their correct locations. (assembly module).



There is a table that defines the movement (angles and displacements) for a part with reference to 0,0,0 so that it fits in another piece. 
So the saddle must be moved to fit the strap, the crosshead must be moved to fit into the saddle, the top pin must be moved to fit the crosshead. etc. 
I am initiating studies in geometric algebra and need a help to: 

(a) Calculate the movement (angles and displacement) of a piece # 4 when it is moved to fit a piece # 3, and # 3 is moved to fit # 2 and # 2 is moved to fit # 1. and so on.
This information will be used in the python script.

(b) Is geometric algebra a good way to calculate this?

Thank you

Ross Mohan

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Mar 2, 2018, 12:22:28 PM3/2/18
to geometri...@googlegroups.com
There is a gentlemen by the name of Peeter Joot who is doing interesting, applied things with GA. Look him up, perhaps on Twitter. 

Hope this helps. 


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alexander arsenovic

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Mar 2, 2018, 12:25:47 PM3/2/18
to Geometric_Algebra
sounds like you just need to cascade a lot of rotors, translators. 
you could probably use clifford for the GA computations in your script. 

Peeter Joot

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Mar 3, 2018, 9:41:14 AM3/3/18
to Geometric_Algebra


On Friday, March 2, 2018 at 12:22:28 PM UTC-5, Ross wrote:
There is a gentlemen by the name of Peeter Joot who is doing interesting, applied things with GA. Look him up, perhaps on Twitter. 

The picture posted doesn't show multiple components interacting in the way described, so I may not understand what is desired.  All the angles in the picture also lie in one plane, so GA may be overkill (but could definitely be used if desired).

Peeter

Robert Herman

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Jun 21, 2018, 8:01:21 AM6/21/18
to Geometric_Algebra
I know it's late to this post, but I am teaching myself GA and I use FreeCAD, but I would like to do more complex geometry to things along these lines:


Using GA in FreeCAD vs. using Rosetta within Racket to AutoCAD.

Any tips on how best to accomplish this with the FreeCAD API which is C++ but has Python scripting?

Rob

Ross M

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Jun 21, 2018, 9:20:00 AM6/21/18
to geometri...@googlegroups.com
Rob, this is a bit (1) wooly-headed and (2) off-the-cuff but any way you can work in a .NET CLR environment, where you could embed both languages?

As a non-developer, that seems like the slick way to do it. Otherwise, I'd look into C++ callouts to Python. Might be considered hacky/kluge-y, but should be possible w/in language

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Robert Herman

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Aug 3, 2018, 1:45:28 PM8/3/18
to Geometric_Algebra
Sorry for the late reply.

I think I am going to have to use a C++ GA library to embed into a fork of FreeCAD, and then create the Python API to it, or call into it.

I thought maybe using Hylang and the Common Lisp GA libraries available, but hey, that's really kludgey!

Rob

On Thursday, June 21, 2018 at 9:20:00 AM UTC-4, Ross wrote:
Rob, this is a bit (1) wooly-headed and (2) off-the-cuff but any way you can work in a .NET CLR environment, where you could embed both languages?

As a non-developer, that seems like the slick way to do it. Otherwise, I'd look into C++ callouts to Python. Might be considered hacky/kluge-y, but should be possible w/in language
On Wed, Jun 20, 2018 at 11:05 PM, Robert Herman <rpjh...@gmail.com> wrote:
I know it's late to this post, but I am teaching myself GA and I use FreeCAD, but I would like to do more complex geometry to things along these lines:


Using GA in FreeCAD vs. using Rosetta within Racket to AutoCAD.

Any tips on how best to accomplish this with the FreeCAD API which is C++ but has Python scripting?

Rob


On Saturday, March 3, 2018 at 9:41:14 AM UTC-5, Peeter Joot wrote:


On Friday, March 2, 2018 at 12:22:28 PM UTC-5, Ross wrote:
There is a gentlemen by the name of Peeter Joot who is doing interesting, applied things with GA. Look him up, perhaps on Twitter. 

The picture posted doesn't show multiple components interacting in the way described, so I may not understand what is desired.  All the angles in the picture also lie in one plane, so GA may be overkill (but could definitely be used if desired).

Peeter

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