IRC log for #brlcad on 20090513

00:48.32 *** join/#brlcad Mike111 (n=mike@cadil21.kaist.ac.kr)
00:48.38 Mike111 hi all
00:51.35 Mike111 I need to generate a NURBS solid (which I understand brlcad currently doesn't support) and export it in IGES format. Ayam can create does NURBS but exports only RIB, DXF, 3DM, 3DMF, OBJ, X3D. Any ideas how convert the Ayam solid into IGES?.
00:59.24 ``Erik um, if I understand correctly, the SVN version of BRL-CAD does actaully support creation, loading and saving of nurbs... there are issues with raytracing at the moment
00:59.53 ``Erik but this subject is more the turf of people who are online in the morning GMT-5
01:00.53 Ralith does the IGES exporter handle them?
01:01.01 ``Erik I doubt it
01:01.28 ``Erik mmmm molten boron
01:01.32 ``Erik futurama++
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01:28.26 Mike111 hi Erik.
01:28.48 Mike111 can I create a NURBS surface which smoothly blends between two 2D cross-sections?
01:46.47 *** join/#brlcad starseeker (n=starseek@bz.bzflag.bz)
01:47.11 starseeker ~log
01:47.11 ibot extra, extra, read all about it, log is http://ibot.rikers.org/%23wowhead/
01:49.28 starseeker uh, shouldn't that be http://ibot.rikers.org/%23brlcad/ ?
01:52.09 starseeker brlcad: I'm wondering if we're going to have to set up a way to store the bounding box trees for nurbs surfaces once generated - it may be that creating them "on the fly" will be almost as bad as tesselating before raytracing
01:54.00 Mike111 hi starseeker.
01:54.23 Mike111 I think the feature I'm looking for is the Ayam Birail2 object: http://ayam.sourceforge.net/features.html
02:00.16 starseeker Mike111: heh, brlcad was just mentioning birails for that application
02:00.32 starseeker feel like implementing a birails primitive?
02:00.54 Mike111 not sure I can ;)
02:01.45 starseeker Well, the ayam source code license is compatible with BRL-CAD's iirc, so you could use some of the logic there
02:02.07 starseeker src/librt/primitives/ holds our current primitives
02:02.13 ``Erik I want a birail prim :(
02:02.14 starseeker hyp and revolve are recent work
02:05.33 ``Erik tell ya what, I can't afford the time to do it, but the birail is important enough to me that I'll totally mentor/help anyone who does that
02:06.28 ``Erik want my damn car back. Want my house fixed.
02:07.36 ``Erik dane cook... isn't actually funny... it's not good
02:09.07 Mike111 I've noticed that configure installs a NURBS library. what is it used for then?
02:12.01 ``Erik that's current development
02:12.33 ``Erik we hope to have solid NURBS capabilties in the very near future, but we're ... still working on it :)
02:13.23 Mike111 that will be good
02:17.44 Mike111 in the meantime, can brlcad import nurbs from Ayam?
02:17.58 Mike111 I understand the DXF format does not support nurbs
02:18.33 ``Erik I think the only nurb import is STEP, and it's ... not 100%
02:19.11 ``Erik like I said before, the people who know that aren't on right now, they'll probably be around in about 10 hours
02:20.12 starseeker IGES is the only working nurbs import
02:20.22 starseeker STEP is being worked currently
02:20.44 starseeker Or there's the 3dm (Rhino) to g conversion if you happen to have Rhino
02:21.01 starseeker IGES produces old (non openNURBS) nurbs right now
02:21.21 starseeker the STEP conversion will create openNURBS nurbs, as does the 3dm-g convertor
02:21.42 Mike111 is `3dm-g' the application name>
02:21.45 ``Erik I thought the iges importer require the tesseleation phase
02:21.48 starseeker yes
02:21.56 starseeker ``Erik: I don't think so...
02:22.25 starseeker If you have access to Rhino, you can model in that and then use 3dm-g to get a .g file
02:22.36 starseeker Doubt that will help with Ayam though
02:22.40 Mike111 is that an opensource?
02:22.46 starseeker Rhino? nope
02:23.02 Mike111 I prefer to rely on opensource only
02:23.12 ``Erik rhino is only $200, not $20,000 though :)
02:23.39 starseeker the Rhino guys are the ones who did openNURBS
02:24.26 starseeker (so the 3dm-g "conversion" doesn't have to do any hard work on the NURBS data structures) ;-)
02:27.31 starseeker has wondered if it might be possible to convince the Rhino/openNURBS guys to add their *->openNURBS conversion logic to the lib...
02:27.44 starseeker probably not though
02:28.30 starseeker Mike111: the basic truth is that there isn't a complete open source NURBS solution that I know of right now.
02:28.47 starseeker One thing about Ayam - IIRC it uses Tk for its interface, just like MGED/Archer
02:29.09 starseeker so you could take a look at their editing support and see how it maps to openNURBS
02:29.35 Mike111 Ayam probably does all I need (plus supports scripting). The problem is getting the IGES file.
02:36.02 starseeker Ayam says it supports 3dm export
02:36.18 starseeker you MIGHT be able to try exporting to 3dm and see if 3dm-g works
02:36.38 Mike111 3dm-g is rhino?
02:36.45 starseeker 3dm is rhino
02:37.27 starseeker remember though, even if you get a .g file, we can't EXPORT openNURBS to IGES any more than we can import them
02:38.13 starseeker so at the very least you'd have to update the IGES export routine to work with the openNURBS data structures
02:39.15 starseeker makes a note to see what 3dm-g does with Ayam 3dm exports
02:42.15 Mike111 what's the difference between standard nurbs and opennurbs?
03:40.23 yukonbob hello cadheads
03:40.28 brlcad starseeker: cross that bridge when we're actually stepping on it, but not unthinkable to store the bb's in some in-memory structure .. could even possibly persist them but even tessellation needs to be "interactive"
03:41.24 brlcad Mike111: we can import nurbs through our iges importer, or through our 3dm importer, but you can't do much more than render them
03:42.52 brlcad ``Erik: iges importer has 3 different import modes, one being nurbs, another being 2D nmg, and another for 3d nmg
03:44.27 brlcad Mike111: the 3dm file format is from the same guys that develop rhino, but 3dm-g is *our* importer for the 3dm format (and doesn't require rhino)
03:45.33 Mike111 can I use brlcad to convert 3dm to IGES?
03:45.51 brlcad Mike111: openNURBS is just the name of the library
03:45.59 brlcad no you cannot
03:46.02 brlcad at least not yet
03:46.21 brlcad because 3dm will import as 'new nurbs' objects, for which there is no iges export support yet
03:47.15 brlcad it really wouldn't be too much work to get it working, but you'd have to work on that code
03:47.28 brlcad or someone would have to, we're not hitting up the converters until a little later
03:47.35 Mike111 but there is technically IGES supports NURBS, that is, it is just an issue of adding the nurbs capability?
03:47.49 Mike111 but technically IGES supports NURBS, that is, it is just an issue of adding the nurbs capability?
03:47.51 brlcad right
03:47.58 brlcad nurbs support on export specifically
03:48.23 brlcad would have to add that logic to our iges exporter to export our nurbs geometry as iges nurbs
03:48.36 brlcad really probably *very* simple
03:48.45 brlcad probably a 1-1 mapping
03:48.50 Mike111 so at the moment there's Ayam which does nurbs but not IGES and brlcad does IGES but not nurbs
03:48.56 Mike111 :(
03:48.58 brlcad :)
03:49.02 Ralith :|
03:49.03 brlcad something like that
03:49.23 brlcad we sort of do nurbs, just no export support :)
03:50.27 Mike111 can I create a nurbs surface in brlcad?
03:50.44 Mike111 I understand it is work in progress
03:51.03 brlcad not interactively via the gui
03:51.25 brlcad only via import (iges/3dm) or programmatically via code
03:51.32 Mike111 I plan to do via a script
03:52.43 brlcad someone would have to add scripting support to our existing new nurbs implementation (probably a days work) for that to work
03:52.58 brlcad as the programmatic access is presently only via C
03:53.32 Mike111 I don't code in C or C++ so I'm afraid I can't help you there
03:54.01 brlcad nods
03:54.21 brlcad it's really not much to add the support, just have to catch a dev with a few hours of free time
03:54.25 brlcad <PROTECTED>
03:55.16 Mike111 specifically, I want to create a surface which smoothly blends 2-D cross-sections. Is this viable in brlcad?
03:55.24 Mike111 I understand from starseeker it is not
03:55.39 brlcad you need a birail primitive for that, which is on our ideas page but not being worked on yet
03:56.11 brlcad or at a minimum, you need sweep support, which is being worked on this summer
03:56.29 brlcad though that will only do very specific/simple blends
03:56.37 Mike111 so there are two features missing (for what I need): script support for nurbs and the birail
03:56.46 brlcad another possibility for you is to use our waterline primitive
03:56.56 Mike111 how flexible will the birail feature?
03:56.58 brlcad you define spline contours
03:57.02 Mike111 what's that waterline?
03:57.03 brlcad those will export to iges too
03:58.22 brlcad what we call an 'ars' primitive
03:59.33 Mike111 will that blend 2D cross-sections?
03:59.59 brlcad yes
04:00.02 brlcad slices
04:00.11 brlcad the blends will be polygonal though
04:00.18 brlcad and depend on your number of slices
04:00.37 brlcad i'll see if i can find some examples
04:01.14 brlcad here's one, http://brlcad.org/gallery/s/screenshots/t62_mged.jpg.html
04:01.18 brlcad that turret is an 'ars'
04:01.42 brlcad see how it tessellates them together, you can see each "layer"
04:02.41 brlcad and fortunately, there's a great page specifically on the ARS on the wiki
04:02.45 brlcad thanks to Ges
04:02.48 brlcad http://brlcad.org/wiki/BRL-CAD_Primitives
04:03.00 Mike111 can you make it smoother, that is, use smaller polygons?
04:03.26 brlcad sure
04:03.35 brlcad read the wiki page, it explains
04:03.46 brlcad number of points per polyline will make it smoother
04:04.13 Mike111 I'm trying to model a wing, so having these polygons isn't practical
04:04.25 Mike111 I need a smooth surface
04:04.44 brlcad it will converge to smooth
04:04.48 brlcad but I understand
04:04.55 brlcad just saying what we have ;)
04:06.20 Mike111 the 2D sections (airfoils) are generated by another application and available as coordinates
04:06.26 Mike111 how can I import them into brlcad?
04:09.12 brlcad you mean as an ars?
04:11.00 brlcad if so, read the wiki page -- it explains all and gives an example (and mged is fully scriptable)
04:11.12 Mike111 I have several 2D cross-sections, defined by plain ascii files (coordinates). how do I create in brlcad a smooth surface connecting them?
04:13.20 brlcad have you been missing everything I've been saying? :)
04:14.15 Mike111 the ars webpage mentions I need to provide the coordinates of all points of the interior polygons.
04:15.36 brlcad you're either using our ars (i.e. faceted and non-smooth), or our dsp (quantized, but smoothable), or manually via polygons (also smoothable), or via an extruded 2D sketch (smooth surface but only linear uniform extrusions), or via nurbs (incomplete), or via birail (non-existent) ;)
04:16.05 Mike111 I'm referring to the ars
04:16.15 brlcad yes, the "interior points" are basically the 2d coordinates
04:16.38 Mike111 that's ok for something like that twisted cube but seems impractical for something like a wing
04:16.40 brlcad "The parameters to the above ars command can be dissected as" ...
04:17.16 brlcad that's only because it's using 4 points per waterline, the first parameter
04:17.37 brlcad you'd want dozens or hundreds of points to smooth it out
04:17.54 brlcad the tank turret is around dozens
04:18.06 Mike111 and I'll need to provide the coordinates for each of these, right?
04:18.24 brlcad I believe so
04:19.32 Mike111 I need to check if that is practical with my application
04:19.37 brlcad nods
04:21.31 brlcad ttyl!
04:23.14 Mike111 thanks for your help brlcad, I'll look into ars later. need to go now
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05:56.52 starseeker winces at the memory of his own run-in with ars
05:58.18 starseeker Ayam seems to export something 3dm-g recognizes as a 3dm file, but my initial stab didn't get anything it felt like importing to the .g
05:58.22 starseeker probably did it in Ayam wrong
06:01.17 starseeker hadn't considered using dsp - boy would that be a strange use of it
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06:56.08 Mike111 is there help available on dsp? it's not in volume II (added lately?)
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07:28.01 CIA-28 BRL-CAD: 03d_rossberg * r34523 10/rt^3/trunk/src/coreInterface/ConstDatabase.cpp:
07:28.01 CIA-28 BRL-CAD: revert changes from revision 34511
07:28.01 CIA-28 BRL-CAD: Sean changed the code in librt so the miss-function hook may now be null as well
07:48.43 CIA-28 BRL-CAD: 03d_rossberg * r34524 10/rt^3/trunk/ (4 files in 2 dirs): added the cone (ID_TGC) primitive
07:51.52 CIA-28 BRL-CAD: 03d_rossberg * r34525 10/brlcad/trunk/misc/win32-msvc/Dll/CMakeLists.txt: included the Cone from the core interface in the brlcad.dll
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10:49.14 d-lo mernin all!
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11:13.19 CIA-28 BRL-CAD: 03Rossberg 07http://brlcad.org * r1442 10/wiki/CoreInterface_PrintTitle_Example: BRLCAD::bad_alloc
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11:48.45 ``Erik shush, you
11:52.05 ``Erik heh, it's been so long since I've updated the fbsd port of BRL-CAD that pedro is lookin gto roll a copy
11:52.28 brlcad so let 'em, nice to share the workload ;)
11:52.46 ``Erik well,
11:52.58 ``Erik the tkhtml issue really screws things over in a big way for that
11:53.28 ``Erik and he wasn't in the loop, so this latest release is going to surprise him
11:54.09 ``Erik will do it today
11:54.14 ``Erik oh, are you in the office right now?
11:54.30 ``Erik brlcad?
11:54.36 brlcad not yet
11:54.43 brlcad eta hour
11:55.01 ``Erik ok, then I'll call. the work is continuing on my front door area, some paint has been laid down, but it's not done yet :/
11:55.12 ``Erik I need to find my usb/miniusb cable to get some pics off my camera :/
11:55.45 ``Erik heh, gonna be out today for house work, and if mondays predictions are right, out tomorrow to return the rental and get my car back...
11:56.15 ``Erik <-- wonders how much he's pissing off the bc with this 'other crap'
11:59.56 ``Erik neat, my phone locked up
12:03.15 d-lo ``Erik: I asked her and she said "Who's Eric?" ;)
12:03.31 d-lo and then I said "Erik, not Eric"
12:03.47 d-lo and she said "oh him. Yeah, its cool."
12:03.53 d-lo so no worries.
12:04.04 ``Erik hah
12:04.24 ``Erik she doesn't get in until 8:30, though? I just got off the phone with admin assist
12:05.26 d-lo TBH, if you are using time you have earned... then don't think twice about it.
12:05.31 ``Erik tell ya what, though, this is pissing me off. it was supposed to be a one day job, this is day #3 without completion and he's figuring on doing some today, then wrapping it up saturday...
12:05.46 d-lo What's he charge an hour?
12:05.54 ``Erik he's predicting time schedules as bad as... as... a software developer
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12:06.03 d-lo HAH!
12:06.05 ``Erik he's charging per project, not hour
12:06.14 ``Erik so he's jacking himself more than anything
12:06.14 d-lo well thats good at least.
12:07.17 ``Erik I just need to make sure I still have enough leave saved up to take two weeks around early july O.o
12:07.19 d-lo Lawn chair + a few stiff drinks + wow on laptop + watching him work = Fun, if nothing else. ;)
12:08.09 ``Erik heh, 'cept I've been inside, trying to clean things up ... or outside giving him an extra pair of hands :) no wow, no watching, ... but yeah, a few stiff drinks ;>
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12:09.48 ``Erik that and learning new songs on my guitar O.o BOC - the reaper and buddy holly - everyday
12:10.37 d-lo LOL, every time I hear the BOC - Reaper, I can't help but start thinking of Cowbell.
12:10.54 ``Erik ayup :D
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12:11.20 ``Erik that's actually the reason I decided to pick it up
12:12.02 d-lo hahahaha.
12:12.16 d-lo I am reduced to tears every time I watch that video.
12:12.51 d-lo There is just something about Walken.... "Let me tell you something. I gotta feva, and the only cure is more Cowbell."
12:13.04 ``Erik indeed
12:13.28 ``Erik if I scrap together another band and do a gig, I so want to say "I got a feva!" right before playing that song :D
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15:18.48 brlcad howdy roberthl
16:01.14 roberthl hi
16:01.26 roberthl I am MinuteElectron, btw.
16:01.35 d-lo I am Iron Man
16:04.26 d-lo Heh, outstanding tutorial: http://www.wikihow.com/Escape-a-Minefield
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20:27.00 brlcad roberthl: I figured :)
20:27.11 brlcad hence the howdy ;)
20:28.51 roberthl ah ;)
20:29.05 roberthl how are things?
20:29.13 brlcad going well
20:29.15 roberthl good
20:29.29 brlcad what are you up to?
20:30.09 roberthl exams for the next couple of months
20:35.35 brlcad fun!
20:35.37 brlcad (not) :)
20:35.51 roberthl hehe
20:51.53 Ralith couple of months?
20:51.54 Ralith wow.
20:52.03 Ralith just got done with the majority of his
21:21.00 roberthl I'm in the UK.
22:31.29 brlcad feel free to nominate us for best project, https://sourceforge.net/community/cca09/nominate/?hash=fec98ebc83402b5dd32313ebe5b215d2 ;)
22:39.53 Ralith wow, sf's been modernizing
22:47.27 brlcad yeah, the design and layout is vast improvement
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