| 00:38.50 | IriX64 | this things still calculating |
| 00:42.38 | Maloeran | Would anyone here be able to clarify a few things regarding conservation of momentum in fluid dynamics? Computation of the dynamic pressure isn't clear to me |
| 00:43.12 | IriX64 | whats the circuit? |
| 00:43.51 | IriX64 | calculate the gs factor that should help, forgotten the formula but it can be looked up |
| 00:44.31 | Maloeran | "gs" factor? |
| 00:44.48 | IriX64 | feedback amplification factor |
| 00:45.18 | Maloeran | I don't think that's related |
| 00:45.37 | IriX64 | ok dynamic pressure in which part? |
| 00:46.14 | IriX64 | need a drawing to do this properly |
| 00:46.27 | IriX64 | can u paste one |
| 00:46.52 | IriX64 | err pastebin or do they allow such? |
| 00:47.40 | IriX64 | need the time constant too |
| 00:48.44 | Maloeran | That might be outside of your usual range. I'm wondering about the computation of the pressure caused by the conservation of momentum in fluid dynamics, hydrostatic pressure and gravitation are easily accounted for |
| 00:49.22 | IriX64 | your pardon, i thought we were talking hydraulic circuits :) |
| 00:50.10 | Maloeran | :) |
| 00:50.17 | deltazap | Maloeran: hang on let me see if my fluid mechanics book is around |
| 00:51.30 | IriX64 | mental note : fluid dynamics != (neccessarily) hydraulics |
| 00:51.41 | IriX64 | :) |
| 00:52.08 | deltazap | ruh roh |
| 00:52.38 | IriX64 | deltazap where are you on the turorial? |
| 00:52.50 | deltazap | finished it today :) |
| 00:53.08 | IriX64 | wonderfull |
| 00:53.27 | Maloeran | Any lead or insight on the topic, deltazap? I'll figure it out eventually.. |
| 00:53.27 | IriX64 | are you going to get that mug made? :) |
| 00:53.46 | deltazap | IriX64: i just sent it off for production today :P |
| 00:53.53 | IriX64 | :) |
| 00:54.08 | deltazap | Maloeran: i'll have plenty of insight on the subject as soon as i can find my book |
| 00:56.15 | IriX64 | been a while since i looked at control systems :) |
| 01:00.56 | IriX64 | thats what I like to see system idle process gets 0% cpu. |
| 01:01.54 | IriX64 | means resources are being fully utilized for the jobs at hand. |
| 01:03.20 | IriX64 | rt sure gets a good chunk :) |
| 01:07.57 | deltazap | Maloeran: are you looking at the differential form of the conservation of momentum or something else? |
| 01:08.34 | deltazap | what you're probably looking for is the Navier-Stokes equation, if that's true |
| 01:10.20 | Maloeran | Right, but unless I'm not looking at this right, it's not clear how to compute the pressure caused by the fluid momentum |
| 01:12.16 | IriX64 | would that not be the upward flow of the fluid? |
| 01:15.54 | deltazap | trying to form answer, hang on :P |
| 01:17.34 | deltazap | i'm trying to think of how to explain it, but i can't come up with anything really good off the top of my head |
| 01:17.57 | Maloeran | Oh.. :) |
| 01:18.56 | deltazap | basically, the movement of the flow causes an oh-so-little compression on the fluid, which is caused by the dynamic viscosity |
| 01:19.40 | deltazap | when you look at the Navier-Stokes equation, the du/dt term is only if you happen to have a changing fluid velocity over time |
| 01:20.27 | deltazap | if you have steady state flow, you can drop that term, move the dp/dx term over, and multiply by rho |
| 01:20.59 | Maloeran | The flow isn't steady though |
| 01:21.24 | deltazap | move it anyways :P |
| 01:21.49 | deltazap | it's been about a year since i even looked at thses problems :X |
| 01:22.09 | deltazap | so, you're given the fluid velocity as u(x,y,t)? |
| 01:22.11 | Maloeran | Fluid dynamics are a bit out of my usual domain too, fairly interesting though |
| 01:22.31 | deltazap | what is your usual domain? |
| 01:22.31 | Maloeran | I'm not given anything but I can compute that from the hydrostatic pressure variations |
| 01:22.51 | Maloeran | Programming ;), not really connected to the world of physics |
| 01:23.36 | deltazap | ah, ok |
| 01:24.21 | Maloeran | Ah hum, it's slowly beginning to make sense |
| 01:26.14 | deltazap | i'd be much more help if i had my other fluid mechanics book on me |
| 01:28.03 | deltazap | and if i could remember this stuff |
| 01:28.49 | Maloeran | Eheh, thanks |
| 01:29.11 | deltazap | it's the differential forms that made all of us cross our eyes in class |
| 01:31.02 | Maloeran | Are you presently still studying? |
| 01:32.27 | deltazap | fluid mechanics? finished that class last summer |
| 01:33.01 | deltazap | my degree? still chugging along. at least i can finally see the light at the end of the tunnel |
| 01:41.16 | deltazap | fluid mechanics is something we really couldn't go very indepth into without heavily hitting PDEs for our problems |
| 01:46.17 | Maloeran | Quite true. I'm beginning to like it though, it's a refreshing challenge |
| 01:47.46 | deltazap | it's so much more different than anything else that we study. it's just so uncertain :) |
| 01:48.31 | Maloeran | Are you in physics? Along with some software programming I hope? :) |
| 01:48.51 | deltazap | actually...no... |
| 01:48.51 | deltazap | i'm in mechanical engineering |
| 01:49.14 | deltazap | with a little bit of programming as a hobby |
| 01:50.16 | Maloeran | *nods* In the vast majority of sciences, I think good programming skills are a major advantage |
| 01:51.13 | deltazap | we're required to take a intro to programming class that's done in maple/matlab |
| 01:52.02 | deltazap | it's a wonderful thing for those who don't know programming, but it's a bit hard to describe things to people when you want to speak of integers, floats, etc. |
| 01:52.58 | deltazap | it helps show how the two are related, but majority of the time, it's hard for people to see the crossover |
| 01:54.04 | Maloeran | For mechanical engineers, I can imagine some computer science concepts may be confusing |
| 01:54.57 | Maloeran | I learned to write C such a long time ago, I think I was 12, the language is really wired in my thinking process |
| 01:55.14 | deltazap | that happens to a lot of people :) |
| 01:59.21 | deltazap | maple is great since it's a math environment that they can get things done quickly in, not to mention that it's interpreted but it can do some really weird things |
| 02:00.44 | Maloeran | Sure, it may be all you need to cover a good range of needs. I would still recommend to pick up some C eventually, if you are interested that is |
| 02:01.03 | deltazap | i can read it quite well, writing is another matter.... |
| 02:01.33 | deltazap | but that should change since i have to do a project in my Cryptography class |
| 02:01.52 | deltazap | implementing 100-digit RSA in C :X |
| 02:02.37 | Maloeran | Sounds easy. I'll trade C programming guidance for fluid dynamic tips ;) |
| 02:03.07 | deltazap | haha |
| 02:08.34 | deltazap | i'm sure the project won't be that bad, the more i read up on RSA |
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| 02:29.02 | IriX64 | why does -ffast-math blow away my floating point precision? |
| 02:43.32 | deltazap | Maloeran: do you have a fluid mechanics book that has problems in it? |
| 02:44.17 | deltazap | if not, see if you can pick up a copy of "Fluid Mechanics" by Robert A. Granger, it's a Dover printed book so you know it's a steal at $35 :) |
| 02:48.46 | Maloeran | My references are wikipedia and a 56000 lines Fortran program at the moment. Getting that book seems like a good idea, I assume there's some focus on computional fluid dynamics? |
| 02:50.18 | deltazap | not really :X |
| 02:51.46 | deltazap | the local college library will have the most information on CFD |
| 02:56.58 | deltazap | ok, i'm not sure what happened to mged, but i'm getting some strangeness with zooming in |
| 02:57.00 | Maloeran | *nods* I think I got the basics right, but I need to integrate viscosity and turbulence into the model |
| 02:57.40 | deltazap | turbulence is going to be a pain |
| 02:57.51 | Maloeran | Yes I'm sure |
| 02:58.16 | deltazap | just about every formula changes when you go from laminar to turbulent flows |
| 02:58.44 | deltazap | for some reason, when i zoom in now, the model just seems to disappear, but it hasn't done this before |
| 02:59.23 | deltazap | and i'm not zooming in that far |
| 03:07.31 | deltazap | and when i do a render at that zoom level, it appears just fine |
| 03:07.43 | deltazap | but there's nothing in the model view |
| 03:08.30 | Maloeran | brlcad really is the one who can help with mged around here |
| 03:08.38 | deltazap | yeah, i figured |
| 03:08.40 | Maloeran | Or occasionally Erik if you are lucky |
| 03:17.49 | IriX64 | corrupted stack .... great :( |
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| 03:32.06 | deltazap | ack! now it's behaving! |
| 03:32.09 | deltazap | i don't get it! |
| 03:32.34 | deltazap | figures mged would crash -_- |
| 03:33.05 | Maloeran | If you describe the problem you had a bit, brlcad might be able to figure something out |
| 03:33.46 | deltazap | alright |
| 03:36.05 | deltazap | brlcad: when i draw one of my files from the tutorial, it looks fine. then, when i go to zoom in, portions of the model just disappear, but i know that i haven't clipped through them yet because when i do a quick raytrace, they appear as normal |
| 03:37.39 | deltazap | what's strange is that everything reappeared as normal right before mged just stopped responding |
| 03:50.16 | deltazap | it seems that only that one model file does it |
| 04:51.51 | IriX64 | using code just generated to produce the .g files, neat trick :) |
| 05:31.30 | Twingy | http://js.cx/~justin/mingw/mingw_msys_instructions.txt |
| 05:31.47 | Twingy | ^-- MinGW/MSys stuff if interested |
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| 14:37.57 | CIA-21 | BRL-CAD: 03brlcad * 10brlcad/configure.ac: need AM_CONDITIONAL for BUILD_CUBIT |
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| 17:11.35 | IriX64 | deltazap: my drawings... parts of them wink out as X tries to keep up depending on whatt I'm doing |
| 17:12.26 | IriX64 | if you're using ogl tho, I don't know |
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| 17:36.15 | deltazap | i know that if you zoom in far enough, you start to clip into the model |
| 17:36.41 | IriX64 | does it stay gone? |
| 17:37.29 | deltazap | no, i'll reappear |
| 17:37.58 | deltazap | but the problem i had yesterday was that parts would disappear when i know that i hadn't clipped through it |
| 17:38.14 | deltazap | but it's only that one file, so i don't know |
| 17:38.34 | IriX64 | not a quirk of the display manager then? |
| 17:39.17 | deltazap | don't think so |
| 17:40.07 | IriX64 | if its only one file... maybe like terra.g it too causes problems |
| 17:42.25 | deltazap | i'll check that one out as well |
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| 19:35.10 | dodi | hello |
| 19:35.31 | dodi | i am looking for a simple tool to create a ground plan of a room, including furniture |
| 19:46.58 | dtidrow_work | lol |
| 19:48.09 | dtidrow_work | well, trying to use brlcad for that would be akin to using a MOAB to take out a bug :-) |
| 19:49.17 | dtidrow_work | now if you wanted to make a really nice looking raytraced image/movie of the resulting room, then brlcad would be useful |
| 19:50.10 | brlcad | doable, though -- also depends moreso on the purpose of creating that plan, and what type of plan |
| 19:51.10 | dtidrow_work | well, yeah, it's doable, but... |
| 19:51.25 | dodi | i just need a simple 2d drawing.. to try moving furniture around and see whats best way to place them.. i dont need more features then this and dont want to learn using a big tool with rich features which i dont need at all |
| 19:51.48 | dtidrow_work | yeah, that's about what I thought |
| 19:52.17 | dtidrow_work | something like Visio for room planning :-) |
| 19:52.54 | brlcad | dodi: yeah, then brl-cad will probably be overkill or at least not what you're looking for -- you can generate the model and diagrams easily enough, but the learning curve is steep |
| 19:53.02 | brlcad | see the tutorials on the website to get an idea |
| 19:53.08 | brlcad | in particular, volume II |
| 19:56.50 | dodi | thats really too much to read for my small requirements *gg* |
| 19:58.10 | dodi | i tried finding something with google, but i got lost in hundreds of cad utilities ;) |
| 19:59.43 | brlcad | there's only a couple open source projects -- nothing really comes close |
| 19:59.50 | brlcad | there's a sea of commercial |
| 19:59.51 | dtidrow_work | heh, that's the problem with google - you generally get either hundereds of hits, or nothing at all |
| 20:00.21 | dtidrow_work | I wonder if dia could do the job... |
| 20:00.37 | dtidrow_work | assuming that dia has templates for typical room furniture, that is |
| 20:03.23 | dodi | i will try dia.. looks good and simple at the first sight ;) |
| 20:03.31 | dodi | thank you :-) |
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| 21:57.25 | CIA-21 | BRL-CAD: 03jlowenz * 10brlcad/include/ (vector_x86.h vector_fpu.h vector.h): fix fold() implementation problem (now left/right versions) |
| 21:58.20 | CIA-21 | BRL-CAD: 03jlowenz * 10brlcad/include/brep.h: need to cache brep in specific structure, since internal goes away |
| 21:59.36 | CIA-21 | BRL-CAD: 03jlowenz * 10brlcad/src/librt/g_brep.cpp: debug shot routine (not returning the right answers yet ;-) |
| 22:01.25 | CIA-21 | BRL-CAD: 03jlowenz * 10brlcad/src/proc-db/brep_cube.cpp: add region creation, so it's easy to raytrace |
| 22:02.22 | CIA-21 | BRL-CAD: 03jlowenz * 10brlcad/src/proc-db/ (brep_simple.cpp Makefile.am): add simple unit cube, for debugging purposes |
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| 22:26.46 | tedcx | are there any examples in the CVS tree? |
| 22:38.22 | tedcx | <PROTECTED> |
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