Hi Sean,
Probably BRL-CAD's strongest feature is solid ray tracing. We've invested more time and effort than anyone I know of in verifiable and validated geometric analysis, and we do it fast.
Ok, thats a very special niche you have there. Besides high energy particle physics, radar perception and nuclear explosions I know no use-case for engineering? I work in the automotive field and our main simulation instrument nowadays are FEA.
We're already there. We adopted the openNURBS library for BREP/NURBS representation support. That's the Rhino3D library which they put out to encourage 3DM format adoption. We picked it up and extended it (an understatement) for our more elaborate purpose. We've since implemented most of the hardest algorithms that they stripped out (NURBS ray tracing).
Uhhh, why the hell openNURBS!? Its just a proprietary data structure for importing/exporting. It has no algorithms at all. And import/export STEP and ray tracing are not the hard algorithms you would need for a FOSS BRep modeling kernel. You need all boolean operations (hard), offset on non trivial geometry (really hard), fillets and chamfer on non trivial geomtry (very hard), draft angles on non trivial geometry (hard) and many many more. OCC have all these, and the STEP converter also (a very good one I might add). So IMO you have still a long way to go for basic stuff OCC/OCE already has. OCC has now a liberal license (LGPL) is very actively developed and has a strong community arm (with OCE, Salome, Netgen,....).
So thats my main puzzlement, why do you go so separate ways to the rest of the FOSS CAx community? Do you have DARPA funding and not allowed to use something from the French? Or is the LGPL the problem? I saw you going mainly for MIT,BSD and Apache.
I disagree whole-heartedly. I honestly believe it's possible to rally dozens of man-years around an open source kernel that is actively-developed by the open source community (not any single company). I know guys on the core devs teams for a number of the commercial products and their 100-1000 person development teams are formidable. However, the same could be said of the compiler landscape just 15 years ago.
Yes your right, I believe that too. But for me this kernel is OCC! You sold me no reason why not.
OCE/OCC is well known, but that's an involved discussion for another day. Most of my issues with it are philosophical and historic, not technical. I believe the open source community can do better.
You consider OCC not as open source? Why? I know, the French company is sometimes special, but since the LGPL switch and the appearance of the OCE project (fork) I would consider OCC/OCE fully Open Source. BtW the Debian guys and the Red Hat lawyers have the same opinion....
By the way, our motto is simply "Open Source Solid Modeling". We've gone to great lengths to extricate ourselves from our military legacy beyond screenshots and legacy documentation. Our new website set to be unveiled soon should make that even more clear.
Good, "Solid modeling for strong defense" is a bit hard to digest in the rest of the world
Good talking. For the purposes of GSoC, I'm going to shelve this collaboration for now but hope we can keep the discussion going. My near-term goal for now is to work towards faithful export/import between our systems. STEP will likely achieve that, but we can see where we're at after this summer.
Yes, enough of words
I agree fully with you, interesting discussion and I hope it goes on.
What I summarize for me:
1) Supporting another FOSS CAD-kernel (yours) is IMO not a option. Too far behind and no real benefit to see... (sorry)
2) I know now some of strong points of BRL-CAD, and will send gladly people your way which seek that stuff. Actually we had some particle physicist on the forum which asked exactly for what you offer!
3) I see BRL-CAD more as a simulation tool (like Calculix or OpenFoam) which I would like to support.That means mainly:
a) read your legacy data CSG STEP files and build up a FreeCAD feature group which result in the the same (BRep) model (like we do it with OpenSCAD). That would give you a migration path of your legacy CSG data into BRep. You can say what you want, you will have to abandon your CSG heritage. I don't think your defense industry models the new weapon systems in BRL-CAD. They will use Catia, Pro-E or NX and you will get Brep STEP files to simulate.
b) make sure the data exchange of models works really good (via STEP-BRep). I don't know how many post-processing BRL-CAD is offering, but your simulation capabilities in that field are very valuable and - indeed - unmatched!
I don't know how far you want to go building up your actual modeling. In that field we are practically competition. If asked
I would suggest you leave the modeling to us and concentrate on your unique capabilities in large scale solid raytracing! Thats a pretty good field in itself! You will get your simulation geometry anyway from a BRep modeler the one way or the other. Not even the insane money in military projects will pay in the long run for modeling a weapon system twice!
So, thats MY opinion. Our community has maybe a different one. Again apology if I was rude.
Jürgen