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The big players nearly all use D-Cubed 2D DCM https://www.plm.automation.siemens.com/global/en/products/plm-components/2d-dcm.html https://www.plm.automation.s

The big players nearly all use D-Cubed 2D DCM https://www.plm.automation.siemens.com/global/en/products/plm-components/2d-dcm.html https://www.plm.automation.siemens.com/global/en/products/pl... Siemens PLM - NX and SolidEdge Dassault - CATIA & SolidWorks Autodesk - Inventor & Fusion PTC - not sure ProEngineer's original sketcher predates 2D DCM of course because they invented history-based feature modeling for 3D CAD. OnShape also. Russian systems tend to use LEDAS https://levindavid.blogspot.com/2011/10/providing-geometric-solvers-be-it.html https://levindavid.blogspot.com/2011/10/providing-geometric-... 2D DCM is now owned and sold by Siemens PLM but originally created by John Owen at D-Cubed Ltd (Cambridge UK) from circa 1989 before he sold the company to Siemens in 2004 https://www.plm.automation.siemens.com/global/en/our-story/newsroom/siemens-press-release/42648 https://www.plm.automation.siemens.com/global/en/our-story/n... Original 2D DCM paper by John Owen from 1991 Algebraic Solution for Geometry from Dimensional. Constraints http://papers.cumincad.org/data/works/att/9ad2.content.pdf http://papers.cumincad.org/data/works/att/9ad2.content.pdf (The split the graph into biconnected components doesn't really cover variable radius circles though.) Other more recent papers by John Owen on arXiv https://arxiv.org/search/math?searchtype=author&query=Owen%2C+J+C https://arxiv.org/search/math?searchtype=author&query=Owen%2... (Some of these are for 3D DCM.) Disclaimer: D-Cubed Ltd employee from 1995-2000.

gilleain 5y ago
Interesting links, thank you. As for splitting the graph into biconnected component, that mirrors what I know about automated layout of graphs (essentially the same problem?) in that it makes sense to have a very high-level algorithm of: 1) split graph into bi- (or tri-) connected components 2) layout these components individually 3) layout the block-tree of components With the goal for layout to make it 'look nice' in some sense, while the goal for CAD is more that the constraints should ... make the final structure buildable and the 'right' shape?
IshKebab 5y ago
Interesting, though I have to say I found Solvespace to have a much more stable solver than SOLIDWORKS. It's a really solid CAD modeller, it just has some critical missing features - notably no bevels/chamfers/drafts.
- phkahler 5y ago
  >> Interesting, though I have to say I found Solvespace to have a much more stable solver than SOLIDWORKS. The original author of solvespace said the same thing. He set out to make a constraint solver that behaved more intuitively than the commercial ones he'd used. He still licenses the solver for commercial use.
ramboldio 5y ago
Am I the only one to find it crazy that basically all of engineering is using the same proprietary constraint solver that only one company knows how to build? Sounds like a big Achilles heel to civilization in some ways.. :D I mean, even with search engines, there is more competition..
- samwillis 5y ago
  It isn’t just the constraint solver, almost all of above use either Parasolid from Siemens PLM or ACIS from Dassault Systèmes for their geometric kernal: https://en.m.wikipedia.org/wiki/Parasolid https://en.m.wikipedia.org/wiki/Parasolid https://en.m.wikipedia.org/wiki/ACIS https://en.m.wikipedia.org/wiki/ACIS Even Autodesk use a fork of an old version of ACIS they own: https://en.m.wikipedia.org/wiki/ShapeManager https://en.m.wikipedia.org/wiki/ShapeManager
- Chris_Newton 5y ago
  Disclosure: I also used to work at D-Cubed, on the 2D constraint solver, but I haven’t for a long time and I’m speaking only for myself here. Am I the only one to find it crazy that basically all of engineering is using the same proprietary constraint solver that only one company knows how to build? Perhaps, but it’s a surprisingly complicated problem and at the same time a highly specialised one. Having the big players in the CAD world, who all need to solve much the same problem here, essentially funding a small group of specialists enough to work on it might just be economic incentives doing their job. I have no insider knowledge about this, but given that D-Cubed was first bought by UGS (a customer, and a direct competitor of many of its other customers) prior to becoming part of Siemens, I expect the lawyers all had provisions in place to deal with any dependency concerns.
  - ramboldio 5y ago
    Yes, I can see why this is great for the big CAD vendors. Not so great for CAD vendors which still need to get big.. It probably also becomes clear now why Russian systems use a different product.. :D
freemint 5y ago
Has the word Homotopy continuation ever appeared in proposals for new solver designs?

gilleain 5y ago

Interesting links, thank you. As for splitting the graph into biconnected component, that mirrors what I know about automated layout of graphs (essentially the same problem?) in that it makes sense to have a very high-level algorithm of: 1) split graph into bi- (or tri-) connected components 2) layout these components individually 3) layout the block-tree of components With the goal for layout to make it 'look nice' in some sense, while the goal for CAD is more that the constraints should ... make the final structure buildable and the 'right' shape?

IshKebab 5y ago

Interesting, though I have to say I found Solvespace to have a much more stable solver than SOLIDWORKS. It's a really solid CAD modeller, it just has some critical missing features - notably no bevels/chamfers/drafts.

phkahler 5y ago
>> Interesting, though I have to say I found Solvespace to have a much more stable solver than SOLIDWORKS. The original author of solvespace said the same thing. He set out to make a constraint solver that behaved more intuitively than the commercial ones he'd used. He still licenses the solver for commercial use.

ramboldio 5y ago

Am I the only one to find it crazy that basically all of engineering is using the same proprietary constraint solver that only one company knows how to build? Sounds like a big Achilles heel to civilization in some ways.. :D I mean, even with search engines, there is more competition..

samwillis 5y ago
It isn’t just the constraint solver, almost all of above use either Parasolid from Siemens PLM or ACIS from Dassault Systèmes for their geometric kernal: https://en.m.wikipedia.org/wiki/Parasolid https://en.m.wikipedia.org/wiki/Parasolid https://en.m.wikipedia.org/wiki/ACIS https://en.m.wikipedia.org/wiki/ACIS Even Autodesk use a fork of an old version of ACIS they own: https://en.m.wikipedia.org/wiki/ShapeManager https://en.m.wikipedia.org/wiki/ShapeManager
Chris_Newton 5y ago
Disclosure: I also used to work at D-Cubed, on the 2D constraint solver, but I haven’t for a long time and I’m speaking only for myself here. Am I the only one to find it crazy that basically all of engineering is using the same proprietary constraint solver that only one company knows how to build? Perhaps, but it’s a surprisingly complicated problem and at the same time a highly specialised one. Having the big players in the CAD world, who all need to solve much the same problem here, essentially funding a small group of specialists enough to work on it might just be economic incentives doing their job. I have no insider knowledge about this, but given that D-Cubed was first bought by UGS (a customer, and a direct competitor of many of its other customers) prior to becoming part of Siemens, I expect the lawyers all had provisions in place to deal with any dependency concerns.
- ramboldio 5y ago
  Yes, I can see why this is great for the big CAD vendors. Not so great for CAD vendors which still need to get big.. It probably also becomes clear now why Russian systems use a different product.. :D

freemint 5y ago

Has the word Homotopy continuation ever appeared in proposals for new solver designs?