IRC log for #brlcad on 20070728

00:09.54 *** join/#brlcad yukonbob (n=yukonbob@whthyt224-180.northwestel.net)
00:50.51 brlcad MinuteElectron: sounds good, I can take a look at it as well (though I'll be working on ldap first)
04:26.00 poolio brlcad: hmmm I want to port my code to scheme 8)
04:26.21 brlcad heh
04:26.28 brlcad you been talking to ``Erik or something
04:27.07 poolio naw. I've just been meaning to learn scheme and ran through the first bit of SICP and it looks enticing
04:27.41 poolio ent.hispeed.ch�
04:27.42 poolio |20:11| � yukonbob ��> �n=yukonbob@whthyt224-180.northwestel.net�
04:27.42 poolio |20:52| <@ brlcad> MinuteElectron: sounds good, I can take a look at it as well (though I'll be working on ldap first)
04:27.45 poolio Day changed to 28 Jul 2007
04:27.48 poolio christ
04:27.57 poolio i need to fix my synaptics driver
04:29.58 poolio okee, fixed :D
04:49.45 yukonbob poolio: what code do you want to port to scheme?
04:56.52 brlcad his genetic algorithm code
04:56.56 brlcad beset
05:03.50 yukonbob hey brlcad ;)
05:04.26 brlcad howdy bob
05:04.28 yukonbob interesting timing, cause I've been thinking of getting into scheme for some time too, and finally made a project for myself to play with it...
05:05.10 yukonbob interfacing guile w/ silc lib... and that made me think of guile bindings for brlcad ;)
05:05.26 brlcad swig bindings would be better
05:05.32 brlcad then you'd get guile for free
05:05.57 yukonbob there you go -- swig is on my list of things to learn more about...
05:06.12 yukonbob how's it going sean?
05:10.05 brlcad pretty good
05:10.22 brlcad almost time to get ready for siggraph in a week
05:10.27 yukonbob !nice
05:10.34 CIA-29 BRL-CAD: 03brlcad * 10brlcad/HACKING: inform the T2 package maintainer of linux releases
05:10.41 yukonbob how long is that event?
05:10.47 brlcad trying to get a new release out as well as finish up another code event beforehand
05:10.52 brlcad it's about a week
05:11.34 yukonbob how integrated is the in-memory format <--> renderer
05:11.51 brlcad what do you mean?
05:11.55 yukonbob ie: how tough would it be to use povray (for example) to render brlcad scene.
05:13.24 brlcad wouldn't be too hard, but easiest would be to write a g-pov geometry exporter
05:13.31 brlcad povray's format is pretty straightforward
05:13.39 yukonbob or the renderer that ships w/ blender, or any arbitrary renderer...
05:13.45 brlcad it'd be one of the easiest exporters to write
05:13.50 yukonbob cool.
05:14.00 brlcad likewise for an importer
05:14.21 brlcad povray actually has loads of good overlap with our format as they also support CSG
05:14.30 brlcad and implicit primitives
05:15.00 brlcad the only difference would be dealing with non-solid geometry (povray will render non-solid, brl-cad does not)
05:15.33 yukonbob right, pov ray generates shells, basically, iirc.
05:15.40 brlcad need explicit format geometry to do most of the cel rendering techniques
05:15.51 brlcad otherwise, something like rtedge is in that direction
05:16.43 yukonbob I was playing w/ rtedge other week, and it was generating lots of horizontal artifacts (ie: horizontal lines sweeping off the curves)... is that typical?
05:16.58 brlcad those povray shells could probably come in as nmg geometry, or even plate mode bots (which allows for thin-surfaces)
05:17.50 brlcad no, that's not -- that was a bug in a particular version, if it's what I'm thinking you saw
05:17.54 yukonbob you've lost me there brlcad, but no matter... I've still got dem conversion and docbook before I get involved with anything like renderers...
05:17.57 brlcad should be fixed
05:18.41 brlcad ahh :)
05:18.55 brlcad hopefully 8.5 final isn't too far away
05:19.09 yukonbob gotta be Real Soon Now(tm)
05:19.15 brlcad that was part of the premise of moving to it, though need for critcial features too
05:19.41 yukonbob oh, it'll all work out for certain... it's just a goofy transition atm
05:19.49 brlcad yeah
05:19.59 brlcad first time we've ever had/needed to
05:20.27 brlcad usually way more cautious/hesitant on the upgrades
05:21.44 brlcad if you get to the point of needing commit access, just let me know
05:22.31 brlcad the door is fairly open to new devs so long as I can continue to review all commits with enough diligence
05:22.45 yukonbob will do -- soon, hopefully, I'll be able to dedicate some more contiguous chunks of time...
05:23.24 yukonbob brlcad is still managed by cvs, no?
05:24.24 brlcad that will be changed before the year's end, but yes
05:25.14 yukonbob is there anonymous checkout avail?
05:25.15 brlcad yeah, still on cvs for the time being
05:25.18 brlcad ~cadcvs
05:25.18 ibot To obtain BRL-CAD from anonymous CVS: cvs -d :pserver:anonymous@brlcad.cvs.sourceforge.net:/cvsroot/brlcad login && cvs -d :pserver:anonymous@brlcad.cvs.sourceforge.net:/cvsroot/brlcad checkout -P brlcad
05:25.32 yukonbob nice
05:28.42 yukonbob brlcad: you a schemer/lisper?
05:28.59 brlcad I've written some lisp over the years
05:32.49 brlcad these days, alas mostly limited to emacs snippets but it's good enough to satisfy the itch
05:33.14 brlcad for a long while, I've wanted to have a BRL-CAD major mode for .g files that lets you browse the geometry contents (ala tar mode)
05:45.30 yukonbob sigraph starts next week (monday)?
05:45.56 yukonbob *siggraph
05:46.06 poolio brlcad: when are you gone?
05:50.34 yukonbob ahh --- 6-9Aug
05:51.38 brlcad starts on sat/sun next week
05:51.49 poolio eek
05:51.50 CIA-29 BRL-CAD: 03brlcad * 10brlcad/src/other/ (tcl/unix/.cvsignore tk/unix/.cvsignore): ignore tcl/tk lib products
05:52.15 brlcad poolio: yeah, eek :)
05:52.45 poolio brlcad: I was hoping to be done work before the 10th :\
05:52.56 yukonbob brlcad: are you looking forward to anything in particular when you attend?
05:53.06 brlcad yukonbob: yeah, the whole thing :)
05:53.12 yukonbob lol
05:53.13 brlcad siggraph is a great conference
05:53.22 brlcad so much to see and do, it's really "big"
05:53.33 poolio any booth babes like at E3?
05:53.38 poolio *they used to have at E3
05:53.52 brlcad once the expo starts, yeah some :)
05:54.16 brlcad though the expo is only during the latter half, and not nearly as crazy booth-babe-wise as E3
05:55.23 brlcad a great balance of deeply technical content with artistic taste and entertainment
05:55.36 poolio cool. I'm jealous
06:00.52 yukonbob bring us back T-shirts: "My friend went to siggraph 2007 and all I got was this lousey t-shirt"
06:07.47 brlcad I get a shirt every year :)
07:03.56 brlcad MinuteElectron: .htaccess are re-enabled
07:15.37 CIA-29 BRL-CAD: 03poolio * 10brlcad/src/gtools/beset/ (beset.c fitness.c population.c fitness.h population.h): fitness function should be working, so selection must be broken
07:17.36 *** join/#brlcad louipc_ (n=louipc@bas8-toronto63-1088754591.dsl.bell.ca)
07:18.19 poolio brlcad: errrr
07:18.26 poolio http://poolio.org/files/bad_convergence.png
07:19.18 poolio but I must sleep, I probably won't be around til late tomorrow
07:19.26 poolio good night/mornin'
08:48.19 *** join/#brlcad Laniakea (i=clock@217-162-231-247.dclient.hispeed.ch)
10:06.53 *** join/#brlcad docelic (n=docelic@212.91.113.199)
11:27.43 *** join/#brlcad andy__ (n=andy@82-43-116-127.cable.ubr01.mort.blueyonder.co.uk)
11:28.13 andy__ Hello
11:45.14 *** join/#brlcad b0ef (n=b0ef@062016141081.customer.alfanett.no)
12:53.51 MinuteElectron brlcad: Will sort everything out in 1 or 3 weeks time.
14:58.36 *** join/#brlcad poolio (n=poolio@c-69-251-3-107.hsd1.md.comcast.net)
15:03.33 *** join/#brlcad Twingy (n=justin@74.92.144.217)
15:14.30 *** join/#brlcad Laniakea (i=clock@217-162-231-247.dclient.hispeed.ch)
16:39.45 *** join/#brlcad elite01 (n=elite01@dslc-082-082-073-056.pools.arcor-ip.net)
19:04.14 *** join/#brlcad Laniakea (i=clock@217-162-231-247.dclient.hispeed.ch)
20:07.47 Maloeran This is a strange question, but... does someone know how video playback in mplayer can take only 0.1% of one processor core? Can it really be that Nvidia drivers provide hardware mpeg4/xvid decoding? I can't really see any other explanation
20:11.23 ``Erik um, given that mpeg (and jpeg) are based on breaking small areas (like 8x8) into simple regions with parametric systems (like, 16 different variants, iirc)
20:11.55 ``Erik I think it'd be totally possible to make a very simple ogl accelerlated mpeg/jpeg display using 16 textures and gauroud shading for the color aspect...
20:12.19 Maloeran As far as I know, Xv provides hardware color space conversion and scaling, there's no decoding involved
20:12.30 ``Erik Xv != GL
20:12.41 ``Erik *shrug*
20:12.53 Maloeran Indeed, but I'm looking at mplayer using 0.1% of one core just using the Xv driver
20:12.57 ``Erik at one point, I was going to write an ogl mpeg decoder, but *shrug*
20:13.04 ``Erik fast cpu's, I guess?
20:13.14 ``Erik mpeg is a pretty simple format
20:13.17 Maloeran While I'm told that Mark has trouble playing back high-definition videos on his dual-core laptop
20:13.35 ``Erik heh
20:13.59 ``Erik winderz has trouble doing something simple like, y'know, booting
20:14.00 ``Erik O.o
20:14.01 ``Erik :)
20:14.19 Maloeran :) Meh
20:14.36 Maloeran I gave him 1024x768 videos, about 1mb per second of compressed data, and he says it's jerky
20:14.52 Maloeran And mplayer doesn't get above 0.1% of cpu use when decoding here, I really don't get it
20:15.01 ``Erik mebbe the codec is the biggie?
20:15.28 Maloeran I used the msmpegv4 codec on purpose, the Microsoft variant of mpeg4
20:15.30 ``Erik I would suspect that standardized codecs would be disadvantaged on winderz, while ms codecs would groove right along
20:15.35 ``Erik heh
20:15.43 Maloeran So that windows users can play the video without having to install codecs
20:15.56 ``Erik is that the usual form for .avi files?
20:16.17 Maloeran It's a common codec for .avi files, yes
20:16.32 ``Erik tell mark to quit running all those viruses and porn shit? :D
20:16.45 Maloeran I sent him high quality x264 videos and such long ago and he never managed to play them
20:16.47 ``Erik is he using like a p166 laptop? O.o
20:16.57 Maloeran A Core 2 Duo laptop
20:17.09 ``Erik erm, so a mac, not winderz?
20:17.15 Maloeran Oh, it's windows
20:17.25 ``Erik those use core duo's now? heh
20:17.34 Maloeran He also has Linux installed although he doesn't know how to use it
20:17.45 ``Erik pointy hairs
20:18.00 Maloeran Anyhow, I'm a bit annoyed because I have no idea how to fix that "problem"
20:18.16 Maloeran I don't suppose you have any thoughts?
20:18.21 ``Erik ask him to use a slightly less inferior machine? hehehhe
20:18.37 ``Erik I'd suspect he has other processes gobbling cpu at the same time
20:18.40 Maloeran It's a good machine, I have seen it. I have no idea where the slowness comes from
20:18.48 ``Erik so the winderz 'process manager' might provide clues
20:19.01 ``Erik <-- has no simple 'quick fix'
20:19.43 ``Erik probably outlook or word running some ugly macro, heh
20:19.55 Maloeran msmpeg4-v2 decoding, very simple stuff, just 1024x768 at 20 frames per second, 1mb of compressed data to read per second... I'm sure I could run that on my amd-k6!
20:20.31 Maloeran Mmmhm, carbohydrates
20:20.48 ``Erik 'cept smothered in shredded bacon and cheese and sour cream, heh
20:20.48 ``Erik :D
20:20.50 ``Erik mmm, fat.
20:20.58 Maloeran Oh. :)
20:21.37 Maloeran Is it possible that windows wouldn't have video drivers installed and use Vesa or something? I thought they had passed that stage
20:22.11 Maloeran Perhaps the machine has trouble pushing 60mb of data to video memory per second *shivers*
20:22.21 louipc that's unfortunate
20:25.02 Maloeran Okay, it's confirmed, the video plays smoothly on an AMD-k6 333mhz with windows 98. But not a manager's Core 2 Duo laptop
20:25.15 Maloeran not on* a
20:26.04 louipc no way!
20:26.15 Maloeran As I said, I don't understand it either
20:26.21 louipc Vista? hehhe
20:26.35 ``Erik um, perhaps the driver cofnig is all effed up and he's doing it all sw?
20:26.37 ``Erik *shrug*
20:26.41 ``Erik with multi-copy buffers?
20:26.43 ``Erik *shrug*
20:26.59 ``Erik or perhaps the machine figured out the operator has pointy hair and is being mean? :D
20:27.15 Maloeran http://www.rayforce.net/m1a2.avi - Here's the video if anyone happens to be on windows
20:27.29 Maloeran Eheh Erik, I like that hypothesis :)
20:28.43 louipc how about if I'm in Linux?
20:29.24 Maloeran It should play very smoothly as far as I can see, 0.1% of cpu use here
20:32.30 louipc ~30% for me but I have an old machine
20:36.15 ``Erik played without noticable cpu utilization usin gVLC here, on a powerbook pro 2.0
20:36.30 ``Erik with 'world of warcraft' running, to boot...
20:36.39 louipc hah
20:36.47 ``Erik two processessors, 3 lights, first hit?
20:36.49 Maloeran I really wonder how the video decoding can be so cheap, it's puzzling me
20:37.07 louipc mine's a 866MHz PIII
20:37.14 Maloeran That's correct. The two processors got 4 cores each though
20:37.27 ``Erik ah, so that's an 8 cor epass to push that 20 fps
20:37.42 ``Erik and I was about to be impressed :>
20:37.59 Maloeran I'm sorry I wasn't up to the task :)
20:38.30 ``Erik 20 fps at that rez on even 8 cores is not trivial
20:38.41 louipc not quite a regular desktop
20:38.43 ``Erik imagine running 1/10 the tirangles, like an ogl came
20:38.45 ``Erik game
20:39.01 ``Erik (that's the shell m1 from the cinema site, right?)
20:39.19 Maloeran Yes, it's the same M1 model Justin gave me about two years ago
20:39.27 ``Erik probably NOT the best model to be showing around, btw, I think it's a limited distribution dealie
20:39.49 ``Erik yanking the havoc or hilux might be safer :)
20:39.50 Maloeran Hum. I was told I could "show" it around, but not distribute it
20:39.59 Maloeran Where can I get these?
20:40.00 ``Erik by justin...
20:40.21 ``Erik I surspect that he was techinically funding when he 'distributed' it to you
20:40.32 ``Erik havoc is in the brlcad repo, unencumbered
20:41.01 ``Erik I believe the hilux has been approved for unencumbered distribution, but hasn't actually been shoved in the repo yet... video of it should be no issue, though
20:41.13 ``Erik given subcontractor relation
20:41.47 Maloeran Thanks, I'll have a look at the Havoc
20:43.25 Maloeran Oh. Video decoding uses XvMC, for which there are Nvidia drivers for hardware decoding. Neat stuff
20:44.13 ``Erik heh
20:44.18 ``Erik cool
20:46.07 Maloeran Eh yes, looks like it has already beenn done
20:46.55 ``Erik hum, that page is all like 6 years old
20:47.52 ``Erik in fact, that first item is implemented in gtk1.2
20:48.14 ``Erik and goes back to gtk 0.30
20:48.17 ``Erik iirc
20:48.28 ``Erik '96ish
20:48.31 ``Erik mebbe '97
20:49.12 ``Erik the salt and cheese on those taters are so making me want more salt and cheese !#~! O.o grar.
20:50.02 Maloeran Mmhm :). I'm just curious, you kept your university user so many years after you left?
20:50.16 ``Erik heh, anti-kosher... pig mixed with cheese, sheesh
20:50.23 Maloeran As I assume math.missouristate.edu is where you once stsudied
20:50.25 Maloeran studied, too
20:50.44 ``Erik yes, when at the uni, I volunteered tutoring to a professor in the math dept, and still aid him in trickier sysadmin duties
20:50.54 Maloeran http://www-rocq1.inria.fr/gamma/download/affichage.php?dir=MILITARY/&name=Y4937_Biotank - That is one mean looking tank
20:50.57 ``Erik in return, I have an account as long as te dept has a machine
20:51.23 Maloeran Nice
20:51.35 ``Erik same guy who gave me the 2 hour crash course in omfg real quaternions
20:51.49 ``Erik which is why I have a slightly different view of them than your typical ogl coder
20:52.26 ``Erik um, I MIGHT be able to get you some other models, like a real t62 (with guts)
20:52.32 ``Erik I'll have to talk to people, though
20:52.40 ``Erik and it'd come in BRL-CAD format
20:53.00 Maloeran *nods* I understood quaternions after staring at code using quats for 2 weeks in high school, and just playing with the numbers a lot. It's not a typical approach
20:53.13 Maloeran It's fine, I got a g2rtgg converter
20:53.38 ``Erik I kinda got a rough overview of a coders view of quats... then went to the prof and got the mathematical background, so a lot of the weird coder shit became obvious
20:53.54 ``Erik like groking that it's 3 imaginary orthogenal axis with a real scalar
20:54.11 Maloeran Yes, I got that part. I have very little mathematical background
20:54.34 Maloeran "A proof? What's that? Meh, just write the code to test 1 billion cases over the night."
20:55.06 ``Erik ah, but a proof isn't worth 1billion tests, it's worth infinity tests
20:55.42 Maloeran Sure so, but something can be "true enough" for me after 1 billion cases :)
20:55.46 ``Erik program provability is a skeery but awesome path in computer science
20:56.08 ``Erik and the difference is between "good enough" and "omfg right"
20:56.20 Maloeran Eheh, well put
20:56.33 ``Erik if you're painting a display for a vidoe game or sim, whatever, but if peoples lives are on the line, i'd rather have a provable system
20:56.37 ``Erik :)
20:57.07 Maloeran True. I'm just definitely not a mathematician
20:57.48 ``Erik me, iether... I'm just old, and becoming more and more concerned with 'critical' software and the reprecussions of an oops
20:58.08 Maloeran Many years ago, I solved integrals by observing relations between solving integrals by brute-force and the original equation. I didn't know the background, I didn't even know what the word "integral" was or meant, but it worked for me
20:58.30 ``Erik integrals are trivial to brute force
20:58.52 ``Erik the notion of "an area under a curve" is easily understnadable by just about anyone
20:58.53 ``Erik :)
20:59.00 Maloeran Sure, and I used that to obtain the real integral, from which deductions can be made to directly obtain any integral
20:59.41 ``Erik of course, for some curves, you can only approximate given a statement of range.. :)
20:59.58 ``Erik without dropping to a base numerical solver
21:00.34 Maloeran I'm still very much biased towards "brute-forcing" my way through problems, in order to find better solutions, rather than mathematically proving anything
21:00.47 ``Erik <-- has a fistful of solvers in haskell and scheme...
21:00.50 louipc :(
21:01.04 ``Erik and my solvers generally tend to be 2-5 lines of code and work faster than the equivelant 3 pages of java or c++
21:01.08 ``Erik :)
21:02.21 Maloeran In a programmer's world, maths are impure anyway, all numbers got limited precision. True mathematial proofs can end up false when applied
21:02.36 ``Erik not true
21:02.48 ``Erik there are mechanisms to deal with true numbers
21:03.02 ``Erik 'scheme' does it automatically, and for C, there are libraries such as gpm
21:03.24 ``Erik the issue is if you're willing to pay the cost for the accuracy
21:03.28 ``Erik and that's an engineering decision :)
21:04.41 Maloeran Are libraries such as gpm strictly correct even with irrational numbers?
21:04.57 *** join/#brlcad docelic (n=docelic@212.15.170.100)
21:05.27 ``Erik I believe so... I think gpm deforms to an unlimited form when the ieee format is insufficient
21:05.41 ``Erik so it's slow and has teh ability to gobble buttloads of memory
21:05.49 ``Erik but will give you omfg right values
21:05.53 Maloeran Sure, but the square root of 2.0 is never going to be exact unless you store it sqrt(2) directly
21:06.12 Maloeran Meaning the complexity of your number becomes a long equation which is totally impractical
21:06.24 ``Erik <-- unsure of exactly how gpm handles that
21:06.55 Maloeran I don't know either, but I suspect that even gpm wouldn't be strictly "true" mathematically speaking. True proofs can end up false
21:07.13 ``Erik be interesting to explore that
21:07.16 Maloeran http://www-rocq1.inria.fr/gamma/download/affichage.php?dir=MILITARY/&name=Y4937_Biotank - Ah, I really like that model, it's just so ugly! I think I'll send Mark a video of it
21:07.42 ``Erik is that the same on you sent earlier?
21:08.03 Maloeran Same url, yes
21:08.08 ``Erik no one dues fugly like the french *sigh*
21:08.14 ``Erik s/u/o/
21:09.06 ``Erik germans may have fat chicks with horns on their helmets, but the rench have... that...
21:09.06 ``Erik :D
21:09.08 Maloeran On the battlefield, I would laugh if faced with such a vehicule. It could be a terribly weapon
21:09.17 Maloeran terrible*
21:09.51 ``Erik but I bet the back of the vehicle is ok to look at... f it's french, that's the part any opposing force would see... O:-)
21:09.58 Maloeran I'm reaally not finding where the M1 came from
21:10.18 louipc wtf is that? haha
21:10.27 ``Erik then it's probably a model worth avoiding :(
21:11.00 ``Erik even though it's legit and shit, ti could still cause issues when small minded people make idiotic assumptions
21:11.13 ``Erik (like that no non-US person could ever do any tech worth doing... a common but WRONG view)
21:11.43 Maloeran That's a... common view?
21:11.55 ``Erik among small minded people, yes
21:12.11 ``Erik I have no other explaination for the fucktarded export laws in the us
21:13.47 Maloeran I'm still amazed by how so many americans know little about the world out there, it's a big planet
21:13.59 ``Erik *shrug*
21:14.12 ``Erik I've talked to equally ignorant people from many other countries, including canuckia
21:15.04 ``Erik people around toronot, sheesh
21:15.06 ``Erik all kinds of special
21:15.07 ``Erik :)
21:15.25 louipc :O
21:15.44 Maloeran I think there's just too much misplaced patriotism, heavily fed to the population by the medias, it's kind of scary
21:16.19 ``Erik that's the vocal minority, I hope
21:16.31 Maloeran Patriotism blinds people to the fact, it narrows their mind. It's socially harmful, yet it's seen as a good thing down there
21:17.25 Maloeran I hope so too, Erik, I certainly do
21:20.11 louipc there was an issue with citizens of certain countries doing work on US helicopters
21:20.34 louipc where bell helicopters had to lay them off, I think they were still canadian citizens too
21:22.03 Maloeran Yes, I remember hearing about this. You once deported a canadian citizen travelling to the states, an university professor, to Syria... because he had dual-citizenship with Syria. That was weird
21:22.28 louipc rcmp tipped off us authorities, mistakenly though
21:24.16 Maloeran Erik or anyone else, what would you recommend as way to find out the "top level" region list to pass to db_walk_tree() to be able to read out a model?
21:24.35 ``Erik 'tops'?
21:24.37 Maloeran I'm a bit tired of having to look into the .g files for some kind of appropriately named string
21:24.48 ``Erik mged -c file.g tops
21:24.51 Maloeran How would I do it from code?
21:25.06 Maloeran This is for the g2rtgg extractor, which is based from Lee's code
21:25.12 ``Erik um, I don't remember, heh, but the 'tops' command sould be fairly easy to find
21:25.27 ``Erik I'd imagine it's a variant of the 'ls' code
21:26.52 ``Erik an os unto itself.. *cough*
21:31.46 Maloeran Hum, I guess I'll look into that. It's kind of annoying this task of having to find the name of whatever you are looking for in the file, I wish I could just say "all of it"
21:33.04 ``Erik the tops command gives you the top level entities
21:33.22 ``Erik given those and the ability to traverse recursively, you have 'all of it'
21:33.41 ``Erik you'd have to look into the specific implementation, though :) I dunno off teh top of my head
21:34.37 Maloeran Yes, I'm trying to make sense of librt/wdb_obj.c
21:40.41 Maloeran I'm not actually finding any Bags Of Triangles in havoc.g, I guess the geometry would have to be triangulated, somehow
21:45.37 ``Erik yeah, the nmg routines
22:10.17 tessier_ How does brl-cad compare to something like autocad?
22:10.39 tessier_ I am looking for something to design model airplanes and do some solid modeling.
22:11.10 tessier_ Calculate surface areas, make sure internal components fit, plot patterns for gluing onto materials for cutting etc.
22:13.22 louipc yeah I think BRL-CAD is good for that sort of thing
22:13.28 louipc not really for drafting though
22:13.35 ``Erik not so much plotting patterns
22:13.41 ``Erik but figurng out if things fit, yeah...
22:13.51 tessier_ Well, it can print out a 2d diagram onto paper right?
22:13.57 louipc not really
22:14.06 louipc (drafting)
22:14.18 tessier_ hrm...how can it do all these other things but not handle that?
22:14.24 ``Erik it's more an analysis tool, not a building tool
22:14.25 louipc no clue haha
22:15.36 ``Erik the kinda core intent is to have a good 'complete' model, pop a ray through it and get a solid understanding of what that ray hits, the depth of the hit, in and out normals, ... a 'segment list', so drafting shtuff just ain't there
22:16.24 ``Erik (for the last twenty or so years, every dollar has been thrown at figuring out how bullets go through things, not anything construction oriented... so it's weak in that area... feel free to improve it, it's open source :D )
22:16.39 tessier_ So Linux still has no good drafting tools? :(
22:17.04 louipc tessier_: qcad is what people use pretty much
22:17.05 tessier_ ``Erik: Yes although full scale stuff is a possibility also.
22:17.15 tessier_ louipc: Funny. I used to host the qcad website. :)
22:17.20 louipc if you're familiar with autocad qcad is easy to pick up
22:17.22 ``Erik <-- cut off a finger doing r/c, wants to get back into it... mebbe doing ellectrics
22:17.22 louipc hahah
22:17.25 tessier_ But it has always seemed like a toy to me. But that was years ago. I should check it out again.
22:17.28 tessier_ ``Erik: Electrics rock now.
22:17.34 ``Erik http://math.missouristate.edu/~erik/finger/
22:17.37 ``Erik so I've heard
22:17.45 tessier_ louipc: In fact, I convinced the qcad author to go GPL. But in 95 or so.
22:17.56 louipc yeah I'm not so much a fan but, it works I guess
22:18.02 ``Erik one of my buddies, the guy who did the oepnnurbs shtuff (jlowenz) is into electrics...
22:18.04 tessier_ Can I import things from qcad to brl-cad in any way?
22:18.09 louipc dxf
22:18.22 ``Erik 2d things in dxf don't xfer to brlcad so very well
22:18.25 tessier_ I am into gliders and electrics. I used to do gas way back in high school (early 90's) but the electric stuff is so much better now.
22:18.57 louipc tessier_: nice about the GPL :D
22:19.07 ``Erik I tried gas in '90 or so, backed off, did it again in '03/'04, hwacked my finger and have been too chickenshit to bothr since
22:19.28 tessier_ ``Erik: You will prefer electric then. You probably whacked your finger starting or adjusting mixture right?
22:19.45 ``Erik adjusting one of twingy's planes, yes
22:19.48 louipc :D
22:19.50 ``Erik after I lost one
22:19.52 tessier_ Electric is so much nicer. You never have the engine sitting around idling and you have no problem with mixture or starting.
22:20.02 ``Erik that's why I've been thinking about it :)
22:20.16 louipc and you can use it for stealth reconnaisance?
22:20.18 tessier_ Hopefully a combination of qcad/brl-cad can do what I need
22:20.18 ``Erik but the ~600 drive cost ... unless it's dropped a lot
22:20.29 tessier_ ``Erik: No way dude. Get a speed 400 powered plane. Dirt cheap.
22:20.38 tessier_ $10 for the motor, maybe $40 for the ESC, I don't recall.
22:20.43 tessier_ Another $20 for a battery and you have a whole power system.
22:20.46 ``Erik if you can hack C and tcl, please feel free to 'fix' brlcad, yo
22:20.48 louipc whoa
22:20.51 ``Erik BRL-CAD rather
22:20.52 tessier_ Actually motors might be way cheaper now.
22:20.59 ``Erik brlcad might not appreciate being fixed :>
22:21.04 louipc ``Erik: that does get confusing haha
22:21.07 tessier_ ``Erik: That's another thing: I kinda wish brl-cad were scriptable in lisp or something like autocad.
22:21.12 tessier_ Doing things in C these days is just silly.
22:21.13 ``Erik oh, me too
22:21.16 tessier_ But I understand brlcad is very old.
22:21.18 ``Erik I'm a scheme geek
22:21.24 ``Erik but BRL-CAD is married to tcl
22:21.37 tessier_ ``Erik: Me too although I have never really done anythign with scheme. I've read the Little Schemer and a few other books though.
22:21.38 louipc tessier_: you can script in Tcl
22:21.49 tessier_ louipc: Yeah, tcl isn't too bad.
22:21.54 ``Erik there's been talk about hooking it into 'swig', but so much of the math shtuff is macro based, it becomes undoable
22:21.54 tessier_ I'm just not as familiar with it.
22:22.35 ``Erik I'd imagine that it wouldn't be TOO terribly difficult to develope a lithp variant on tcl
22:23.01 ``Erik turing complete is turing complete, y'know
22:23.42 louipc Linux is silly
22:23.49 ``Erik your mom is silly
22:24.02 louipc :O
22:24.08 tessier_ Maloeran: For the most part that is true. Programmer time and buffer overruns are expensive.
22:24.16 ``Erik C is good for low level things... *shrug* linux is a hair better than winderz, not bsd cool, but *shrug* :)
22:24.24 louipc a hair!
22:24.36 tessier_ ``Erik: The vast majority of stuff is not low level.
22:24.52 louipc yeah true
22:24.53 ``Erik I completely agree, tessier... but mal was about ready to drop a brick in his shorts there ;>
22:25.10 ``Erik <-- tends to use ruby or scheme as a first shot for most things these days
22:25.33 tessier_ ``Erik: Only because he has been coding C for years and cannot appreciate how much more efficient higher level languages are because they represent a threat to the usefulness of his existing knowledge. :)
22:25.43 ``Erik hahaha
22:25.46 ``Erik uh oh
22:25.52 ``Erik don't say nothin' 'bout assembly, mal will pop!
22:25.53 ``Erik :D
22:25.55 ``Erik *duck*
22:25.55 tessier_ Efficient in terms of programmer time (and therefore money) and darn near as efficient in terms of cpu cycles too.
22:26.17 Maloeran tessier_, buffer overruns is a silly programmer mistake, bad programmers shouldn't use C to begin with. Some complex tasks are actually less bothersome to perform in C, for it really lets you do what you want to do
22:26.18 ``Erik it's a matter of how assess value to developer time
22:26.26 ``Erik ooooooold people tend to put a lot of value on time
22:26.31 ``Erik young folk tend to view it as 'free'
22:26.39 Maloeran Plus of course, efficiency of good C code can hardly be compared with any scripting language
22:26.39 tessier_ Assembly is fun for understanding how architectures work and for programming microcontrollers.
22:27.17 tessier_ Maloeran: But programmers aren't perfect. They have been making that mistake for decades. Even the best ones. They are inevitable.
22:28.06 Maloeran Indeed. And that's why good Operating Systems have some security features, so that we won't pay a global hit in performance just in case there's a buffer overrun somewhere
22:28.20 ``Erik sometimes, I look at some of their stuff and go "fucking brilliant", other times, I go "wtff"
22:28.42 ``Erik heh, so you're using obsd these days, mal? :> *duck*
22:28.53 tessier_ Critical loops that get executed zillions of times can be in C and assembly. Anything else, including word processors and the like which hardly ever use cpu and spend all their time waiting on programmer input, should probably be in a higher level language.
22:29.06 tessier_ That goes for mail servers, dns servers, etc also. They spend all their time waiting on IO.
22:29.20 ``Erik :D
22:29.31 tessier_ Link to a C implementation of your hashtable function or whatever and do all the other silly stuff in a HLL
22:29.38 Maloeran That I agree, languages should be used for what they are best suited for. There's still much room for C out there
22:29.55 louipc yep
22:30.01 tessier_ There's tons of room for C. But I think it is currently taking up more room than it rightfully deserves. :)
22:30.09 tessier_ Fortunately that is changing though.
22:30.10 ``Erik code it in scheme, when you find a bit of scheme that you simply can't make fast enough, rewrite it in C... when you find a bit of C that can't possibly be rewritten to be fast enough, rewrite it in asm... if you find a bit of asm that can't possibly be rewritten to be fast enough, go back to the drawing board, yo
22:30.21 tessier_ ``Erik: Exactly. FFI for the win!
22:30.46 ``Erik <-- feels that c++ and java simply don't belong... they're tools to limit the damage incompetents can do, not tools to extend the ability of competents :(
22:30.51 Maloeran I usually go back to the drawing board before the assembly step, but good enough :)
22:31.14 tessier_ ``Erik: Agreed. I don't see much good use for java. But lots of people are brainwashed with it.
22:31.18 ``Erik (and limited incompetence sucks compared to a little competence *cough*)
22:31.35 tessier_ C++ sure seemed cool way back when and even I would have agreed it was a good way to go once upon a time but I have wisened up since then.
22:31.41 Maloeran tessier_, I think C should be the language of choice for all core libraries and related low-level software, I'm actually worried that it's less being used for new software these days
22:31.57 ``Erik there're bits of jabba I like, I think it's better than c++, but there're bits I dont' like... and in practice, it's grossly abused
22:32.04 tessier_ Maloeran: I guess it depends on where you draw the line for low-level.
22:32.39 ``Erik <-- would rather have a boffo scheme or smalltalk core library than a good C one... *shrug* :)
22:33.05 ``Erik mebbe I'm just sick in the head
22:33.16 louipc they force java in school
22:34.08 Maloeran Sometimes, even C seems too high level for me. Compilers are so incompetent, when one cares about performance
22:34.17 ``Erik when I wasi n college (the second time), the were migrating to jabba the last year I was there...
22:34.19 Maloeran It's so tempting to just get down in assembly for an instant >30% performance boost
22:34.28 Maloeran I think I should do that before Siggraph
22:34.46 ``Erik 30% with no change in linearality can't comopete with even a loss of static and improved 'big oh'
22:34.46 ``Erik <PROTECTED>
22:34.51 tessier_ Maloeran: One rarely needs to care about performance these days. A few microseconds different in my code execution time matters little to me. :)
22:35.13 tessier_ I tend to do a lot of text processing, system administrator type stuff, network IO, web applications, etc.
22:35.16 ``Erik "my assembly form outruns this high level one, up to 10 memory locations... *cough*"
22:35.22 tessier_ IO is always the bottleneck before cpu in my projects.
22:35.46 tessier_ For something like raytracing I can totally see where cpu counts.
22:36.00 tessier_ But few people have the need to implement raytracers.
22:36.18 ``Erik (mal is heavy into high speed raytracing lately)
22:37.11 tessier_ I see.
22:37.16 ``Erik tessier: if you want to make BRL-CAD work for you, we'd be happy to discuss the path from point A to point B, it's mostly a matter of A) not knowing the drafting world so well and B) not having the time to do it :/
22:37.18 tessier_ Maloeran: I bet you use vi. :)
22:37.27 ``Erik hey, shut up, I use vim :(
22:37.37 tessier_ ``Erik: You code scheme in vim?
22:37.40 ``Erik yup
22:37.44 tessier_ I like vim just fine. Been using it for 10 years.
22:37.50 tessier_ But coding scheme in vim seems a bit nutty.
22:37.58 ``Erik there're addons to make it better
22:38.05 tessier_ I learned emacs for programming tasks and use vi for everything else.
22:38.05 ``Erik vim has a dialect of schemme somewhere under the hood
22:38.18 ``Erik a lot more 'normal' compared to modern languages than elithp
22:38.22 tessier_ It bugs me that that they wrote their own extension language for vim
22:38.41 tessier_ I know you can tie python and other stuff into it. But one standard extension language that everyone uses seems like a better way to go.
22:38.42 louipc well there's already sketch objects in BRL-CAD
22:38.51 ``Erik vim has pluggable extensions... mine are built with python, ruby, and the internal scheme/lithp
22:39.00 ``Erik plus cscope, and with the gui disabled
22:39.03 tessier_ If brl-cad doesn't work for drafting it probably isn't what I need. Although I wish I could draft and then produce a 3d model.
22:39.23 tessier_ So I don't have to draw everything twice.
22:39.30 louipc yeah
22:39.35 tessier_ Wish I could draw in a speed 400 motor and then use that same dawing in both.
22:39.46 ``Erik BRL-CAD can do 3d models, and has something called "rtedge" that attempts to do line drawings
22:40.06 ``Erik it cannot do dimension lines at this time, and rtedge is... nonoptimal
22:40.38 ``Erik if you're just wanting something to help cut balsa and place bits, rtedge MIGHT be sufficient
22:40.52 ``Erik not something that can be passed to a machine cutter though
22:41.28 tessier_ I'm not fortunately enough to have a machine cutter.
22:41.52 tessier_ But I would like something I can print 2d blueprints from. I'm not so interested in balsa as I am in composite design.
22:41.55 louipc what needs dimensioning can be arbitrary and needs to be selected by the drafter
22:42.00 tessier_ I make stuff from fiberglass, carbon fiber, expoxy resin, etc.
22:42.09 ``Erik ummmmmmmm
22:42.11 ``Erik http://en.wikipedia.org/wiki/RONJA
22:42.24 tessier_ 2d drawings are mostly for patterns, jigs, etc. And 2d parts fitting and layout planning although 3d would be better for that.
22:42.36 ``Erik that device was designed and raytraced using BRL-CAD by one of the dudes who hangs out here
22:42.51 ``Erik if you go to the web page, he has lots of 'rtedge' displays
22:43.10 ``Erik he even found a funky race condition bug in rtedge :)
22:43.34 ``Erik http://ronja.twibright.com/
22:47.16 ``Erik (unfortunate that he didn't use the multispectral raytracing capabilities to optimize configuration, but *shrug* it got the job done)
22:47.44 tessier_ Wow, that RONJA device is really cool
22:49.26 ``Erik http://ronja.twibright.com/holder/index.php is the output of rtedge
22:49.37 ``Erik with the bug, heh
22:49.59 ``Erik <-- fixed it, but doesn't remember if the fix made it to 7.10.0 or not... 7.10.2 should be out 'any day now'
22:50.07 ``Erik if brlcad would get off his duff O.o :> *duck*
22:50.28 tessier_ What does rtedge do exactly?
22:50.55 louipc cool
22:51.03 ``Erik um, fires proximity rays and if the difference in first hit is above a threshold, draws a line there
22:51.50 ``Erik but at the moment, the threshold is hard coded and more designed for reasonably large vehicles (like, 10m long... think tanks)
22:52.38 tessier_ I see.
22:52.52 tessier_ Ever heard of CADIA?
22:53.14 ``Erik sounds semi-familiar
22:53.38 tessier_ http://www.nextcraft.com/rcprojects.html
22:53.55 tessier_ Check out those models. All rendered in 3d. This guy is a master.
22:54.24 ``Erik hm
22:54.34 ``Erik ummm
22:54.52 ``Erik one of the nifty things of brlcad is the ability to estimate CM, total mass, etc
22:57.03 tessier_ Yes, that could be handy
22:57.40 ``Erik aand there's effort to export to a FEM format, uhhh, 'qubit', which could do flow analysis
22:58.01 ``Erik qubit might not be public, though :/
22:58.14 tessier_ Total mass? So you tell it how much each of the materials weighs etc?
22:58.21 louipc tessier_: what's cadia?
22:59.10 ``Erik yes, every region can have a material associated, density of the material is defined and it can sum it all up
22:59.40 tessier_ http://www.nextcraft.com/nextcraft_products.html
22:59.43 ``Erik I think it's still all done with 'GIFT' materials, which tend to be skewed towards heavier harder things
22:59.49 tessier_ I think cadia is what this guy uses for his 3d models but I'm not sure.
22:59.57 ``Erik like, several kinds of steel, some hard woods, don't think balsa is a standard bit
23:00.02 ``Erik but could easily be added
23:00.02 tessier_ Can I define my own materials?
23:00.07 ``Erik yeah
23:00.18 tessier_ And units? Like draw a speed 400 motor and say it weighs this much and has a center of mass/gravity at a particular location?
23:00.35 ``Erik the .g db understands ints, and there's a materials file that's ascii
23:00.41 tessier_ That would be pretty handy for building models.
23:01.02 ``Erik ummm, it understands units, I dunno if you can skew like that, um, though if you defined the guts of the 400 motor, it SHOULD come out correct
23:01.30 ``Erik or you could make the motor otu of two cylinders (plus surface crap) and assign different 'effective mass' coefficients for the bits to emulate the correct balance
23:03.34 ``Erik the only bit that might be seriously challenging would be shaped bits (nose cones, the inital scoop on the rudder, etc) and skinning :/ otherwise, most r/c planes are awfully simple
23:03.51 ``Erik and 'advanced' primitives like the "pipe" goes perfectly with control gear
23:04.47 ``Erik naturally, the engineering of how to assemble it will be up to the model developer, but with the raytracing abilities, you could 'see' a proposed model at each step of assembly
23:06.12 ``Erik there's even a 'best fit' project on the table that'd go well for laying out how to cut up planks of balsa, once it's implemented :)
23:09.54 ``Erik heh "spel chek"
23:30.05 *** join/#brlcad SWPadnos_ (n=Me@dsl245.esjtvtli.sover.net)

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