#robotics Logs
Nov 07 2018
#robotics Calendar
12:35 AM rue_mohr: wow, there, I can load a dxf
03:52 AM Jak_o_Shadows: ah, cool.
03:52 AM Jak_o_Shadows: I was wondering, cause if you're like just stacking transform matrices everywhere
03:52 AM Jak_o_Shadows: I suppose stacking them is bettr than flattening them though
03:53 AM Jak_o_Shadows: I agree with rue about openscad
03:54 AM Jak_o_Shadows: I might not 100% agree with his solution (through I do think it is pretty good), but openscad is just not wonderful
03:54 AM z64555: hm? transform matrices?
03:54 AM Jak_o_Shadows: and tbh, my solution is the same sort of thing, sketches and extrusions, but more automated.
03:54 AM Jak_o_Shadows: I'm vaguely reading the scrollback
03:55 AM z64555: I need to find out how to get my new IRC client to cull out the join/leave spam :/
03:57 AM z64555: its... in a right-click menu
03:57 AM z64555: well ok
03:57 AM Jak_o_Shadows: What client?
03:57 AM z64555: quassel
03:57 AM Jak_o_Shadows: eyyyy
03:58 AM Jak_o_Shadows: I swapped ti quassel about a year ago
03:58 AM Jak_o_Shadows: I like the bouncer aspect of it
03:58 AM z64555: I think thats its main feature, tbh
03:59 AM Jak_o_Shadows: yeah
03:59 AM Jak_o_Shadows: Do you have it running on a separate pc/server?
03:59 AM z64555: not yet
04:00 AM z64555: I was running on thunderbird for the longest time, rolled email and IRC into one application
04:00 AM z64555: but then gmail decided it didn't like thunderbird
04:08 AM Jak_o_Shadows: ah. I ran pidgin for years
04:08 AM Jak_o_Shadows: But tbh, got sick of being perfectly out of sync with active periods int he channel
08:47 AM z64555: letsee, anybody doing some simulation of kinematic chains? Thought I saw a few blokes interested in walker bots and arms, and the like
08:49 AM z64555: Hitting a bit of snag when the links are weighted, a simple example would be a double pendulum
08:49 AM z64555: The joints have a tendancy to come apart when the simulation is stepped through (I have rendering and physics at different rates)
09:03 AM rue_mohr: no simulation, DO THE REAL THING
09:04 AM rue_mohr: https://www.youtube.com/watch?v=e6RvF4HUTNs
09:05 AM rue_mohr: but it doesn't mean you cant play!
09:07 AM veverak: nice
09:07 AM veverak: I am not profesor yet, I am still pre-doc student
09:07 AM veverak: to run simulation multiple times, I need computers instead of slav... students
09:07 AM veverak: ** pokerface **
09:08 AM rue_mohr: I'm just a hobbyist
09:08 AM rue_mohr: I used povray, so I know how to move objects in 3d space
09:09 AM rue_mohr: a chain like that is easy, you start with a link, rotate it, translate to the next link, rotate, translate, rotate, translate
09:09 AM rue_mohr: and each time you do everything, so it all stays togethor
09:10 AM rue_mohr: would you like a library for 3d manipulation?
09:10 AM veverak: yeah, did that multiple times
09:10 AM veverak: I have one :)
09:10 AM rue_mohr: everyone should
09:11 AM rue_mohr: like an lcd library, I think everybody pre-arduino has made one, not that they had to, they did
09:11 AM rue_mohr: https://www.youtube.com/watch?v=zRdJrE80Vjk
09:11 AM rue_mohr: tom
09:11 AM rue_mohr: Tom_L,
09:19 AM z64555: you start at the end affector or at the root of the chain?
06:58 PM rue_mohr: end effector
06:58 PM rue_mohr: you want to do forward or inverse tho?
08:58 PM z64555: letsee, forward is "have angles, want position" and reverse is "have position, want angles?"
08:59 PM z64555: kinda need both, tho
08:59 PM z64555: sigh, why do I bother with simulations
09:08 PM rue_mohr: you have to break down your goals into priorities,
09:09 PM rue_mohr: what is the smallest thing you can get results with first
09:09 PM rue_mohr: and dont say 'all of it'
09:09 PM rue_mohr: as a programmer this is half your mark
09:09 PM rue_mohr: - break down task
09:09 PM rue_mohr: - implement in available components
09:09 PM zhanx: milestones if you will
09:09 PM rue_mohr: ^^^ thats all programming is
09:11 PM rue_mohr: zhanx, do you know of an xwindows demo for angus' clipper library?
09:11 PM rue_mohr: http://www.angusj.com/delphi/clipper.php
09:11 PM zhanx: no i don't. I know of it, but never use it
09:11 PM rue_mohr: I need to port it to C, which isn't as much of a problem if I can have a working version to maul
09:11 PM rue_mohr: oh, its the polygon clipping library almost everything everywhere uses
09:12 PM zhanx: yea your doing cam, which I haven't done
09:13 PM rue_mohr: well, its a million other things too
09:13 PM rue_mohr: I suppose I ahve to do it blind
09:13 PM rue_mohr: its... just not as much fun
09:13 PM rue_mohr: hey, do you ahve visual C for windows?
09:13 PM rue_mohr: does anyone here?
09:13 PM z64555: I do, any particular version or just the IDE in general?
09:14 PM z64555: or compiler, for that matter
09:14 PM zhanx: does anyone here use windows?
09:14 PM rue_mohr: http://www.angusj.com/delphi/clipper.php
09:14 PM rue_mohr: ^^ I'd like to know if the cpp example in that works
09:14 PM rue_mohr: its kinda important to know if what your starting with works!
09:16 PM z64555: give me a few, have to get things set up
09:20 PM rue_mohr: ooo I forgot how much I hate ifdef
09:21 PM zhanx: ifdef rocks
09:21 PM rue_mohr: iirc this is a non-oop library in an oop wrapper
09:22 PM rue_mohr: zhanx, I'm gonna make a program that will use ifdef to merge two source files like interlaced cards, so that the program you end up with depends on what you defined
09:22 PM rue_mohr: and it'll do it in the ugliest way possible
09:22 PM zhanx: yea thats what its for
09:22 PM zhanx: well you are programming it not me, if i was it would be worse
09:23 PM rue_mohr: right, I need to learn how to use this library before I can recode it.....
09:23 PM rue_mohr: *sigh*
09:24 PM z64555: blah, forgot how to Cmake
09:25 PM rue_mohr: :((( almost 5000 lines of code
09:26 PM rue_mohr: I ahve a program that traces includes in source files, but not one that does function dependencies
09:26 PM rue_mohr: know of any?
09:28 PM z64555: doxygen can make caller graphs
09:29 PM z64555: uuumm. unless I'm confusing it with something else
09:30 PM z64555: dangit, I am. There's the graph that shows you how classes and the like are related, but not a caller graph
09:30 PM z64555: kinda running at 50% brain power right now, sorry
09:39 PM z64555: rue_mohr: that snippet won't work by itself, Aside from the obvious fact that it doesn't have a main block in it, it omits the draw functions
09:41 PM z64555: ah, the zip came with some .sln's premade, letsee how they fair
09:43 PM rue_mohr: cpp/example
09:45 PM z64555: the example in the cpp/opengl dir worked as expected for me
09:45 PM rue_mohr: ok
09:46 PM rue_mohr: yes, opengl is what Iwas aiming at
09:46 PM rue_mohr: I wonder how I can build that for linux
09:46 PM rue_mohr: z64555, thankyou
09:47 PM rue_mohr: knowing that in some context it works, it quite helpfull
09:47 PM rue_mohr: I think I'v tried to do this library before, and it led me to make a whack of stuff in my 2d library
09:50 PM z64555: the console example builds a .svg and lets the system decide what program to open it
09:50 PM z64555: might be a better starting point
09:50 PM rue_mohr: hmm
09:50 PM rue_mohr: I'm still scrolling thru the source...
09:51 PM rue_mohr: the objective would be to express this library in terms of my 2d object librarys components...
09:51 PM rue_mohr: and C it...
09:51 PM rue_mohr: it doesn't seem to be true oop
09:55 PM rue_mohr: the clipperoffset is what I'll want 'first'
09:56 PM rue_mohr: I dont know why this isn't broken up
09:56 PM rue_mohr: this file is crazy
09:57 PM z64555: Thankfully its limited to one file. Imagine about 5 dozen of these
09:58 PM rue_mohr: seperating it into the classes and support functions wouldn't hurt
10:04 PM rue_mohr: http://www.angusj.com/delphi/clipper/documentation/Docs/Units/ClipperLib/Classes/ClipperOffset/_Body.htm
10:04 PM rue_mohr: I'm gonna aim for that
10:05 PM rue_mohr: so, I need to get that path thing working
10:08 PM rue_mohr: typedef std::vector< IntPoint > Path;
10:08 PM rue_mohr: hmm
10:08 PM rue_mohr: IntPoint(cInt x = 0, cInt y = 0): X(x), Y(y) {};
10:09 PM rue_mohr: typedef signed long long cInt;
10:09 PM rue_mohr: I wonder if using doubel really slows things down much
10:10 PM z64555: double is floating point tho
10:10 PM rue_mohr: yea
10:10 PM rue_mohr: this whole thing is integer
10:10 PM z64555: which invariably has minute innacuracies
10:11 PM rue_mohr: but I'v always taken that, on modern processors with FP, there is no speed loss
10:12 PM rue_mohr: to the point this fellow made a 128 bit int library
10:13 PM z64555: pretty much
10:13 PM rue_mohr: there is a reason this library is about 5000 lines
10:13 PM rue_mohr: its like 5 libraries all crammed into one file
10:15 PM rue_mohr: isn't long long 128 bits?
10:16 PM z64555: for 32 bit architecture, int is 32, long is 64, long long is 128
10:16 PM z64555: for 64 bit, double that
10:16 PM rue_mohr: in bytes
10:17 PM rue_mohr: char: 1
10:17 PM rue_mohr: short: 2
10:17 PM rue_mohr: array: 24
10:17 PM rue_mohr: float: 4
10:17 PM rue_mohr: double: 8
10:17 PM rue_mohr: long double: 12
10:17 PM rue_mohr: long long: 8
10:17 PM rue_mohr: short int: 2
10:18 PM z64555: long double, haven't seen that before
10:18 PM rue_mohr: sizeof.c:15:50: error: 'long long long' is too long for GCC
10:18 PM rue_mohr: :/
10:19 PM z64555: the floats, however, I think are constant regardless of arch
10:19 PM rue_mohr: thats from gcc
10:19 PM rue_mohr: sizeof()
10:19 PM z64555: yeah
10:19 PM rue_mohr: the long double is the largest type then
10:20 PM rue_mohr: at 96 bits
10:25 PM rue_mohr: http://pubs.opengroup.org/onlinepubs/009695399/basedefs/stdint.h.html
10:25 PM rue_mohr: apparently only up to 64
10:36 PM rue_mohr: if I just take and start seperating this into classes I wonder whats left
10:36 PM zhanx: students?
10:50 PM rue_mohr: c++
10:51 PM rue_mohr: I dont have enough milk for the tea required to get anywhere with thsi