OT: Math Question ... |
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OT: Math Question ... |
SirAndy |
Dec 30 2004, 11:21 PM
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#1
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Resident German Group: Admin Posts: 41,669 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
stupid question (what else is new) ...
while working on my 3D-Editor/Game Engine i came to realize that the default Rotation Matrix for OpenGL uses a counterclockwise winding for Rotations around the Y-Axis (Yaw), meaning if you look at a Object in the XZ Plane a Positive Angle will Rotate the Object Left, a Negative Angle will Rotate it Right. This is Counter-Intuitive and i am wondering if there is a rule for this behavior in a Cartesian coordinate system or is this merely a "personal preference" for OpenGL ??? My editor currently uses the clockwise approach, where a positive angle rotates the object to the right instead, which seem much more intuitive. searching the web, i have found both approaches, but i would like to know if there's a "corret" way to do it ... (IMG:http://www.914world.com/bbs2/html/emoticons/type.gif) Andy |
dinomium |
Dec 30 2004, 11:32 PM
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#2
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Git on a chair son, all the good stuff is goin over yer head! Group: Benefactors Posts: 2,777 Joined: 2-January 03 From: Bremerton, WA Member No.: 74 Region Association: Pacific Northwest |
polar coordiantes are mesured anti clockwise...
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SirAndy |
Dec 30 2004, 11:44 PM
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#3
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Resident German Group: Admin Posts: 41,669 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
alright, so this would be the correct matrix then:
hmmmm, maybe i will just make it an option for the enduser ... (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif) Andy |
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dinomium |
Dec 31 2004, 01:00 AM
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#4
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Git on a chair son, all the good stuff is goin over yer head! Group: Benefactors Posts: 2,777 Joined: 2-January 03 From: Bremerton, WA Member No.: 74 Region Association: Pacific Northwest |
two quotes for you:
Chevy Chase as President Ford "It was my understanding there would be no math..." or Malibu Barbie "Math is Hard!" (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) either way that is just more trig than I care to remember... and not this close to new years!! |
swood |
Dec 31 2004, 01:14 AM
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#5
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Senior Member Group: Members Posts: 1,839 Joined: 6-February 03 From: Strong Beach Member No.: 251 Region Association: None |
Shoot. I thought this was going to be one of those impossible to solve problems about two trains leaving at the same time travelling towards each other at different speeds. (IMG:http://www.914world.com/bbs2/html/emoticons/blink.gif)
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Gint |
Dec 31 2004, 01:27 AM
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#6
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Mike Ginter Group: Admin Posts: 16,082 Joined: 26-December 02 From: Denver CO. Member No.: 20 Region Association: Rocky Mountains |
Looks like A.f.d bait to me... (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)
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Trekkor |
Dec 31 2004, 02:55 AM
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#7
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I do things... Group: Members Posts: 7,809 Joined: 2-December 03 From: Napa, Ca Member No.: 1,413 Region Association: Northern California |
I was hoping this was some sort of game with a fake prize. (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif)
KT |
Steve Thacker |
Dec 31 2004, 07:01 AM
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#8
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UMMMPH Yea Baby Yea ! UMMMPH Group: Members Posts: 1,089 Joined: 8-January 03 From: Pickerington, Ohio Member No.: 113 Region Association: Upper MidWest |
That's some deep doo-doo Andy..... you flipping developers kill me. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)
Sounds like the rare matting call to attract Alfreds. Almost like Jennette MacDonald and Nelson Eddy I'm calling yooooo hoooo (IMG:http://www.914world.com/bbs2/html/emoticons/w00t.gif) Sorry Andy I couldn't resist (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) |
Red-Beard |
Dec 31 2004, 07:12 AM
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#9
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"Ya canna change the laws of Physics" Group: Benefactors Posts: 1,124 Joined: 11-February 03 From: Houston, TX Member No.: 288 Region Association: None |
_YOU_ are the engineer on a train traveling from New York City to Chicago... Yeah, Standard Polar coordinates are counter clockwise. And they were derived from Standard Carteasean coordinates. |
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ChrisFoley |
Dec 31 2004, 07:32 AM
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#10
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I am Tangerine Racing Group: Members Posts: 7,934 Joined: 29-January 03 From: Bolton, CT Member No.: 209 Region Association: None |
Think of it this way: in an xy plot of a ray beginning at the origin, as the slope increases from zero to ninety degrees (and beyond) - the ray rotates in a counterclockwise direction.
Everything else follows from this example. |
rick 918-S |
Dec 31 2004, 08:24 AM
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#11
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Hey nice rack! -Celette Group: Members Posts: 20,471 Joined: 30-December 02 From: Now in Superior WI Member No.: 43 Region Association: Northstar Region |
What some people solve with math others would solve with a hammer. Hit the coil until you loosen the wires. Then wind them the other way. This should achieve what your after without changing the math. (IMG:http://www.914world.com/bbs2/html/emoticons/happy11.gif)
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Curvie Roadlover |
Dec 31 2004, 08:39 AM
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#12
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Two trunks are better than one! Group: Members Posts: 2,025 Joined: 29-December 02 From: Southeast Michigan Member No.: 42 |
Maybe there's someone out there that could post some scanned articles from old Road and Track issues to explain this (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/alfred.gif)
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michel richard |
Dec 31 2004, 10:24 AM
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#13
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Senior Member Group: Members Posts: 1,291 Joined: 22-July 03 From: Longueuil, Québec Member No.: 936 |
Th best quote in a long, IMHO. |
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john rogers |
Dec 31 2004, 10:36 AM
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#14
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Senior Member Group: Members Posts: 1,525 Joined: 4-March 03 From: Chula Vista CA Member No.: 391 |
I teach a couple of graphics classes using OpenGL and somethings are not really sensible to us normal people?! Try this website as there are many really good tutorials and explanations: http://nehe.gamedev.net/
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KaptKaos |
Dec 31 2004, 10:40 AM
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#15
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Family Group: Members Posts: 4,009 Joined: 23-April 03 From: Near Wausau Member No.: 607 Region Association: Upper MidWest |
"It's a farging trick question!" - Roman Maronie
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Bruce Allert |
Dec 31 2004, 10:43 AM
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#16
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Hellions asleep Group: Members Posts: 3,289 Joined: 19-March 03 From: Eagle Creek, Orygun Member No.: 441 Region Association: Pacific Northwest |
/ v <=> b:© + h(M)
/ angle v dangle <=> proportional to b: beauty of c cutie h heat m meat (IMG:http://www.914world.com/bbs2/html/emoticons/cool_shades.gif) .........einstein (IMG:http://www.914world.com/bbs2/html/emoticons/alfred.gif) .........b |
Sammy |
Dec 31 2004, 11:18 AM
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#17
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. Group: Members Posts: 1,190 Joined: 21-January 03 From: Orange, Ca Member No.: 178 |
My cat's breath smells like cat food.
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sgomes |
Dec 31 2004, 12:05 PM
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#18
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Electric Member Group: Members Posts: 815 Joined: 6-May 04 From: Campbell, CA Member No.: 2,029 |
As Homer said:
Y're all nuts. I'm goin' to Moe's. |
SirAndy |
Dec 31 2004, 01:54 PM
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#19
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Resident German Group: Admin Posts: 41,669 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
that's what i wanted to know. the math is easy, just didn't know if there was a "right" way to do it. counter-clockwise it is then ... easy enough, (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) Andy PS:
PPS:
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rick 918-S |
Dec 31 2004, 06:22 PM
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#20
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Hey nice rack! -Celette Group: Members Posts: 20,471 Joined: 30-December 02 From: Now in Superior WI Member No.: 43 Region Association: Northstar Region |
(IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif) I still think it's easier to rewind the coil. (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) |
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