Dear Thomas, I am sorry if my last e-mail gave the feeling that I was suggesting the integration of every possible engineering tool in pythonOCC. I do not know all the details of the OCC library and I was thinking, because this project about assembly sequence is presented on the OCC website, that it may have been included in OCC. >From that question raised the question: then maybe it's in pythonOCC? Hence my mail but promised, I will be more discreet for next questions :-).
Best regards, Pierre 2010/2/24 Thomas Paviot <tpav...@gmail.com> > Dear Pierre, > > First, rigid body simulation and assembly sequencing are, according to me, > really different topics in term of objectives and expected outputs (the > slideshow attached is quite old, one of my colleague presented a more recent > paper related to this topic at the MOSIM'08 conference) > > The second point is that the objective of the pythonOCC project is not to > cover the huge scope of engineering and implement the best ideas from best > papers published in best journals/conference. It's something that can not be > achieved by a few people. We just aim at providing a platform enabling such > an implementation in the easiest possible way. > > The development strategy can be sum up in a few words: let's take the best > existing free and open source libraries in engineering field, and let's find > a way to integrate them in a new consistent environment. Current pythonOCC > release (0.4) is built upon OpenCASCADE, SMESH, GEOM. Then next one will add > Traits support, OpenDE (rigid body simulation), maybe fem solvers etc. Each > of those libraries are developed by many skilled engineers. The added value > of the pythonOCC project is then the *integration* of these libraries. Free > and open source development model, as well as the use of standards, make > such an integration be achieved by a few motivated people (actually, it's > not demonstrated yet, but I want to prove that it's possible). > > The added value being *integration*, it's out of scope of the project to > develop/implement low-level features such as 'automatic assembly sequencing > from semantics extraction'. > > Best Regards, > > Thomas > > 2010/2/24 Pierre JUILLARD <pierre.juill...@gmail.com> > > >> Dear Thomas, >> >> Following you mail concerning rigid body simulation, I wanted to mention a >> work illustrated on the OpenCascade website concerning modelling of assembly >> and that may be related to rigid body simulation most notably in the >> "detection of contacts" topics. >> >> Here is the link of the documents: >> http://projects.opencascade.org/projects/doc/TheseNRejneri-FR.ppt >> (you can also find the thesis on the web) >> (link of this project: >> http://projects.opencascade.org/projects/assembly.html >> link of the project library page which gathers other interesting links: >> http://projects.opencascade.org/projects/) >> >> I wanted to know if such features are available in pythonOCC? >> Usually, such a management of parts is complex, but is very interesting to >> identify assembly problems. >> >> I thank you in advance for your comments. >> Best regards, >> >> Pierre >> >> >> >> >> >> 2010/2/21 Thomas Paviot <tpav...@gmail.com> >> >>> Dear all, >>> >>> A few years ago, I developed a software aimed at providing rigid body >>> simulation features to Catia V5 or SolidWorks. This project, known as >>> "Decade dynamics", is not active anymore although many users are frequently >>> asking for new features or bugfixes (for your information, a website >>> dedicated to the project is available at http://www.decade-dynamics.org, >>> there also is a PDF document here: >>> http://download.gna.org/decade/decade_A4_recto_basse_def.pdf and >>> http://download.gna.org/decade/decade_A4_verso_basse_def.pdf - All this >>> material is in french, sorry). >>> >>> The limitations I faced when working on that project are the root of my >>> motivation to start the pythonOCC project: >>> - the small 'free' API provided with Catia or SolidWorks (a VB API) is >>> not sufficient to access all internal classes/method, >>> - the complete API (known as CAA for Catia) is very expensive, >>> - there are licensing issues if you ever want to redistribute such a >>> program. I chose to distribute Decade under the GPL license, and never had >>> any problem with software vendors: I never made money with it, there's no >>> real business opportunity, so lawyers dont' care about my work. >>> >>> However, I'm still interested in rigid body simulation, since it's much >>> important when working in the robotics/mechatronics field and, more >>> generally speaking, in engineering. I committed to the pythonOCC subversion >>> the first draft of a DYN package dedicated to rigid body simulation (you can >>> have a look at this video to see the first results: >>> http://www.youtube.com/watch?v=IW5VYbCGFYc). >>> >>> This DYN package is at the same level as PAF(Parametric Application >>> Framework). The set of sub-packages PAF/DYN/MSH/FEM are what we called the >>> 'Level2 API': it's an intermediate layer between the OCC kernel (LeveL1) and >>> the applications that can be built on top of them. The goal is also to make >>> them interoperable, I mean being able to exchange data in a consistent way: >>> I imagine a 3D complex model, made with PAF, simulated with DYN to get >>> forces in joints, checked with a FEM analysis, then optimized according to >>> these results (the design/simulation loop), and finally exported to a STEP >>> file for manufacturing. All of these sub-packages would rely on >>> a semantically explicit knowledge (KBE). Well, this is not a roadmap, rather >>> a long term objective... >>> >>> Please let me know if you have any comment or suggestion, >>> >>> Best Regards, >>> >>> Thomas >>> >>> _______________________________________________ >>> Pythonocc-users mailing list >>> Pythonocc-users@gna.org >>> https://mail.gna.org/listinfo/pythonocc-users >>> >>> >> >> _______________________________________________ >> Pythonocc-users mailing list >> Pythonocc-users@gna.org >> https://mail.gna.org/listinfo/pythonocc-users >> >> > > _______________________________________________ > Pythonocc-users mailing list > Pythonocc-users@gna.org > https://mail.gna.org/listinfo/pythonocc-users > >
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