Dios mio! Maybe try one question at a time next time... :-) On Thursday, March 19, 2009, at 03:12PM, "Bryan Bishop" <[email protected]> wrote:
>I enjoyed our conversation yesterday in the channel. I was wondering >about a few things, and also figure some of the thoughts should be >documented if I'm going to seriously consider GSoC 2009 with BRLCAD >:-). First, some links. (And for the record, I don't know if this >should be counted as an official GSoC application, since I am more >interested in getting feedback at this point.) They can't be counted as official GSoC applications, not how it works. You actually post your application directly through the sochop GSoC site to the BRL-CAD project when the time comes. For now, it's all just discussion. >Can someone help clarify the following section? >""" >Implicit : Constraints implicit in the definition of a primitive : >Tangency or perpendicularity of Vectors, Equality of scalars etc. >Explicit : Constraints explicitly expressed between two or more primitives. > >One of the intricate parts of the work is the actual integration of >libpc with librt. Associated work going on with libpc involves the >creation of a Math Virtual Machine for parsing and evaluating (math) >expressions which would be used for stating the constraints, along >with the grammar. >""" Dawn can explain it in better detail, but consider a simple sphere that is simply stored as a point and two vectors. To be "a sphere", there is an implicit constraint that the vectors are equal in magnitude (equal to the radius of the sphere) and for orientation purposes, they should be perpendicular to each other. Now take two spheres and you might want to guarantee that they are always perfectly tangent to each other -- that'd be an explicit constraint. Or consider just the one sphere and say that you want to require that the sphere always have a radius between 1 meter and 12 meters -- another explicit constraint. Those constraints, whether implicit or explicit are a series of expressions that associate with and refer to geometric entities. The MVM he refers to there is a system for evaluation those expressions and constraints. This is pretty common in most CAD systems where you can fully/under/over constrain a given model. Some even give you a convenient little red light / green light to let you know when you're fully constrained. >GraphSynth >http://graphsynth.com/ Interesting project, assuming it could be made available under some compatible license. Practical integration and portability issues given it was implemented in C#, though. >Example, re: gears >http://heybryan.org/~bbishop/docs/gears/gears.html The registered name servers for heybryan.org (afraid.org) seem to be dead. Might want to consider managing your own DNS via something like zoneedit.com or figuring out why afraid.org's DNS is down. Anything that works is very likely just giving a cached result from before they went down but that should eventually time out. >** Relevant diagrams- ** > [ snip ] All interesting and food for thought, but where were you going with that (all those situational diagrams) again? :) Otherwise, I'd need a concrete use-case example before I could say much of value other than "ok". >constraints problem when resizing, or something?) How about some user >case stories? That would be amazingly helpful. I suspect this code >would be implemented and integrated as the backend constraints >solution engine, but I'm also open to the idea of gluing it together >with shell or command line utilities depending on how exactly it's >supposed to work when seamlessly integrated (just to make sure I >understand completely). Concur that a few test cases are really required. Dawn has worked on a few test cases as part of the low-level work done to date, but there's not yet a high-level set of test cases or use cases of how it will become exposed to a user. >So, if I can get some feedback on those issues, that would be great, >and maybe also whether or not anyone would be interested in my working >on this for GSoC? I have to admit that I'm a little sketchy on some of There is definitely the potential for some conflict here given it was a GSoC project last year. I'd hate to see us lose a capable developer just because two capable guys only applied to the same idea. Are there other projects that interest you or is this the only one? >however has expressed an interest in throwing it up as GPL (or >possibly LGPL), but I feel this is a minor detail and something that >can be fixed. GPL would be a non-starter. LGPL would be okay. BSD is the easiest and most flexible for dependency management. It's only a minor issue if it's not an issue. :-) There are other concerns, though, about the fact that it's implemented in C# that would have to be considered. > [snip] >intense fellow. Hi. Please don't make me list all past programming >projects :-). More stuff on my website for the "about me" aspects- >feel free to email me off-list if this isn't detailed enough, so that >I don't clog the mailing list with "me me me" :-). No need. You could say just about anything and it may or may not be fully correlated with a reasonable representation of you. What I've found to be much more effective is to actually see how folks code. That's why one of our application requirements is that folks provide a patch of some sort. It's a means to evaluate whether students can communicate effectively, productively, have actually worked with our code, can get stuff done, etc. >After looking at Manuel's application, maybe I've gone a bit overboard >here with details? *Waaay* overboard. Fortunately, it's not an application, it's just an e-mail. Try to aim for some clarify of thought, though. ;-) Pleasure to meet you Bryan and welcome! Look forward to seeing how your idea(s) and submission(s) develop. Cheers! Sean ------------------------------------------------------------------------------ Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are powering Web 2.0 with engaging, cross-platform capabilities. Quickly and easily build your RIAs with Flex Builder, the Eclipse(TM)based development software that enables intelligent coding and step-through debugging. Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com _______________________________________________ BRL-CAD Developer mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/brlcad-devel
