irclog2html for #brlcad on 20050603

00:33.25 *** join/#brlcad guu (guu@myth.gibbscam.com)
01:04.44 CIA-5 BRL-CAD: 03brlcad * 10brlcad/ (configure.ac db/Makefile.am): add a --enable-models-install option with aliases for conditionally installing the example geometry models. benchmark geometry are still converted/installed as they are required for the installed benchmark tool
01:08.31 CIA-5 BRL-CAD: 03brlcad * 10brlcad/NEWS: include release note details on the benchmark suite changes/installation as well as the addition of example geometry databases
05:23.08 CIA-5 BRL-CAD: 03brlcad * 10brlcad/src/librt/cmd.c: the command string to rt_do_cmd is no longer modified by this routine so that the caller may use static command strings
05:24.44 CIA-5 BRL-CAD: 03brlcad * 10brlcad/src/rt/opt.c: add a -W option to all of the raytracers that specifies that a 'non-default' (usually inverted) background color should be used. for rt, this is a white background.
05:26.47 CIA-5 BRL-CAD: 03brlcad * 10brlcad/src/rt/ (viewedge.c rtedge.1): the new -W option on rtedge means that the foreground and background colors need to be inverted so that it's black lines on a white background by default. (this implements sf request 1177331)
05:27.35 CIA-5 BRL-CAD: 03brlcad * 10brlcad/src/rt/rt.1: document the new -W option stating that it draws a white background for rt
05:31.35 CIA-5 BRL-CAD: 03brlcad * 10brlcad/NEWS: added -W option to raytracers for white background (implements sf request 1177331)
05:35.28 CIA-5 BRL-CAD: 03brlcad * 10brlcad/src/rt/viewedge.c: only swap the colors once otherwise the frame backgrounds will flop back and forth
05:53.29 *** join/#brlcad PKMOBILE (~Matthew@pcp0011643451pcs.aberdn01.md.comcast.net)
06:01.17 PKMOBILE http://www.monstercrawler.com/beta-bin/nph-beta.pl?qry=nutcase+liberal+websites
06:01.40 PKMOBILE good to know thats how people find me :-\
09:56.35 *** join/#brlcad ping (~ping@ping.phys.ntu.edu.tw)
09:59.27 ping hello!
10:01.46 ping It is great that result of such a long time project is now free software. I'm in a small telescope design team and I'm thinking whether or not I can use BRL-CAD to simulate the imaging of a set of lenses with known surface (shape, size) and material (index of refraction, reflectivity).
10:02.18 ping Any advices are appreciated!
11:44.24 learner hello ping
11:45.56 learner that sounds like a neat project, similar to one I worked on a few years back
11:47.08 *** join/#brlcad d_rossberg (~c28bf505@bz.bzflag.bz)
11:47.58 learner you can definitely use brl-cad for simulating the lens though the default optics may be tricky to get looking realistic
11:51.01 learner gutenmorgen herr d_rossberg
11:51.50 d_rossberg good night Mr. learner
11:52.29 d_rossberg i think i have found a problem in creating bots in mged
11:52.49 d_rossberg the unit taken is always mm
11:53.27 learner creating bots how?
11:53.47 d_rossberg try "units m; in foo bot ...; l foo"
11:54.04 learner ahh
11:54.46 d_rossberg version is 7.2.4, if i remember right
11:55.36 learner sure enough.. just looked at the code and it's missing the local2base conversion
11:56.43 d_rossberg i looked at typein.c, but it look like the conversion is done somewhere else
11:57.43 CIA-5 BRL-CAD: 03brlcad * 10brlcad/BUGS: typein of a bot is not performing a local2base units conversion
11:57.46 d_rossberg OK, i found a call to local2base
11:58.14 learner yeah, it's there -- it's just a simple multiply
11:58.20 learner on the read
11:58.59 learner local2base is already set up with the correct units conversion scaling factor
11:59.12 d_rossberg i took arbn_in as a reference, but couldn't find a significant difference in vertex-handling
12:00.18 learner shoudl be a matter of multiplying just the atof's by local2base, but I'll have to test it some
12:04.25 learner don't forget the thinkness atof if it's a plate
12:04.37 learner er, thickness
12:05.35 learner yeah, looks like it's just those four
12:05.43 learner can you test to make sure that works how you expect?
12:07.21 d_rossberg i hope so (i'll try it)
12:08.02 d_rossberg looks like arbn_in has a similar problem
12:08.20 CIA-5 BRL-CAD: 03brlcad * 10brlcad/src/mged/typein.c: rossberg identifies a bug in bot typein where units conversion was apparently overlooked.
12:08.44 d_rossberg it's not important for the normals, but for the distance parameters there, i would say
12:10.12 learner hmm
12:12.10 learner ahh, yep, sure enough..
12:12.32 learner the rt_arbn_import in librt/g_arbn.c
12:12.39 learner <PROTECTED>
12:12.53 learner <PROTECTED>
12:13.42 learner good catch!
12:15.29 CIA-5 BRL-CAD: 03brlcad * 10brlcad/src/mged/typein.c: rossberg finds another units problem in the arbn typein where the distance paramater is not taking units into account.
12:18.30 d_rossberg i will now check out the developer sources and build it, this may take a while ...
12:19.08 d_rossberg BTW: i can ssh at sourceforge.net :-)
12:19.37 learner :) great
12:20.06 learner i believe the news file is now going to have to be utf-8 :)
12:25.37 CIA-5 BRL-CAD: 03brlcad * 10brlcad/NEWS: fixed units bug in mged typein of bot and arbn
12:37.12 learner heh, i think CIA-5 choked on some utf chars
12:37.53 ping learner: sorry that I left for dinner, and thanks!
12:38.31 learner no problem, and now I go shower :)
12:38.36 ping learner: any pointers to your project? With your permission I'd like to take a look at the code.
12:42.03 learner you don't need my permission, it's openly available
12:42.21 learner or rather 'sure!' you have my permission ;)
12:42.58 learner ping: you can download it from http://sourceforge.net/projects/brlcad/, I'd suggest getting it from CVS if you're a developer
12:43.38 learner and that's a rather interesting choice of irc nicks.. any particular significance?
12:45.27 ping well, that's the transliteration of my first name in Chinese... :)
12:45.46 learner ahh okay :)
12:46.57 learner there's more documentation on the website at http://brlcad.org
12:47.57 ping checking out the codes from CVS now...
12:48.48 ping while waiting for CVS co to finish, I'd like to ask more questions. :)
12:49.39 ping Is there a way to find the size of image on the focal surface for parallel light rays coming from a fixed direction?
12:53.04 learner the image size _on_ the focal surface?
12:54.45 ping yes. The parallel light rays will be focused by the lens not into a point but an image with finite size. The size is a very important parameter in telescope design.
12:58.11 learner there is definitely a means to calculate the size in code since you can traverse the rays and introspect them however you like
12:58.49 learner and similarly the rays are parallel coming from a fixed viewpoint/viewsize by default
12:59.06 ping okay, great. I'll read the documents and learn how to do that. Is this part in the rt library?
12:59.23 learner yes, that would be part of librt
12:59.32 learner as well as parts of liboptical
13:00.22 learner sounds like you either want some information out of liboptical or perhaps even your own varient of liboptical that has you optics behavior
13:00.35 learner perhaps just another shader type
13:02.36 ping I didn't see liboptical in the "top level" of documents, any reference?
13:02.46 learner you could actually draw the light rays in mged and visualize the rays in 3D to observe how they converge.. that would be neat
13:05.47 ping oh, that is cool! I'll try that.
13:06.26 learner basically in the modeler, you can issue plotting commands (actual old-school .pl code)
13:06.34 learner that will draw lines
13:08.00 learner you could run the raytracer in either debug mode, or add some additional printing to give you ray trajectories as they are traversed, and then feed that into something that plots them in mged
13:08.01 ping hmm... does that mean I have to learn a scripting language (.pl)?
13:08.21 learner no no, pl is a simple plotting instruction
13:08.41 learner used on the old plotter devices that used to make schematics
13:10.49 ping that sounds somewhat familiar... :)
13:15.04 learner it depends a lot on what your ultimate goal is, but is sounds like you want to simulate different lenses and observe how they behave?
13:15.41 learner the existing raytrace logic will deal with "pure" lenses as it is
13:16.17 ping that's right. I want to determine the configuration of lenses (size, location, radius of curvature, etc) that produces the smallest image size within budget constraint.
13:16.34 learner but is not set up for the variety of optics effects you encounter in real lenses like subsurface scattering, microfractures, dust/particulates, etc
13:16.57 learner for that you'd have to modify liboptical or write a similar variety that takes those into account
13:18.14 ping I think I'm doing an "idealistic" simulation for now so microfractures can be ignored.
13:18.44 ping I think one big challenge might be the "Fresnel lens" where the surface of the lens has many "teeth".
13:19.09 learner the raytracers (e.g. 'rt') deal with generating the rays, librt takes over and shoots/propagates the rays through a given scene reporting on when/where objects are hit, liboptical takes over when objects are hit telling it how the ray should react (does it scatter, diffuse, reflect back, etc)
13:20.39 learner then the results are passed back to the raytracer from librt and liboptical for it to decide what to do with those events/values
13:21.19 learner which is usually something like generate a picture (rt), report on some mass/volume (rtweight), draw object outlines (rtedge), etc
13:22.20 learner sounds to me like you're sort of wanting a raytracer that generates plot lines which wouldn't be too difficult at all
13:22.33 learner in fact there was a debug flag at one point that did that.. hrm
13:23.58 ping oh, where is that debug flag?
13:26.37 learner i'd have to hunt, but it should be either the -x flag to rt, with flags described in include/raytrace.h
13:27.00 learner I'd love to continue this but I unfortunately have a meeting .. i'll be back in a bit
13:27.45 ping sure! (am compiling the source code right now)
14:54.12 CIA-5 BRL-CAD: 03d_rossberg * 10brlcad/include/raytrace.h: the caller may use static command strings to rt_do_cmd
14:59.34 ping the CVS version has a compile error in src/librt/cmd.c:193... need to replace "const char *ilp" by "char *ilp" and "register const ..." by "const ..." to get it compiled.
15:02.19 d_rossberg learner: i couldn't build BRL-CAD from CVS because of undefined "yyin" etc. in brlcad/src/tab/scriptsort.o
15:02.46 d_rossberg ping: my last commit fixed this problem
15:05.17 d_rossberg ping: but because of slow replication it may be better to fix it by hand now:
15:08.01 d_rossberg ping: include/raytrace.h line 2701 should be "const char *ilp,"
15:22.23 ping oh I fixed it by replacing the function argument types in src/librt.cmd.c
17:53.30 brlcad yeah, sorry about that -- I forgot to commit a header file last night
20:27.43 *** join/#brlcad PKMOBILE (~Matthew@pcp0011643451pcs.aberdn01.md.comcast.net)
20:28.13 PKMOBILE stop drop and roll... the nutcase liberal with a website is here!
21:16.06 *** join/#brlcad CIA-5 (~CIA@flapjack.navi.cx)

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