Timeline for Quaternion understanding
Current License: CC BY-SA 3.0
15 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Sep 20, 2011 at 13:58 | vote | accept | Fabian | ||
| Sep 20, 2011 at 10:23 | answer | added | Maik Semder | timeline score: 3 | |
| Sep 20, 2011 at 10:16 | answer | added | FxIII | timeline score: 2 | |
| Sep 20, 2011 at 10:15 | comment | added | Maik Semder | @Fabian, yes, you will also need the up-vector though | |
| Sep 20, 2011 at 6:41 | comment | added | Fabian | If its the case (Matrix.lookAt is creating a view matrix) is there a straight forward way to create a quaternion from Position + Target vector ? | |
| Sep 20, 2011 at 6:30 | comment | added | Fabian | Hello, For my tansformation framework, it is DirectX API, so I think it is linked to row-vector matrix convention. I have quaternion mainly because its a more compact way of sharing a rotation than a matrix. (you have a network layer exchanging the quaternion data). So you thing that it could come from the Matrix.LookAtRH ? I will check it. | |
| Sep 20, 2011 at 0:11 | comment | added | Nathan Reed | @ChristianRau, there's no "mathematical justification" either way. It's just a convention. It would be nice if it was universally one way or the other, but unfortunately both conventions are in widespread use. Column vectors are dominant in pure math, but row vectors are used quite often in applied contexts...but maybe the latter is not that important for you. :) | |
| Sep 19, 2011 at 22:45 | comment | added | user4513 | Tbh, Im learning row-vector matrices in my uni course, so I guess that makes your comment subjective and without proof. But theres a thousand discussions on this, no result. Its like OpenGL vs DirectX, its not what you have, but how you use it. | |
| Sep 19, 2011 at 22:41 | comment | added | Christian Rau | @Daniel obviously! | |
| Sep 19, 2011 at 22:40 | comment | added | Christian Rau | @Nathan I was educated with column-vectors. I have never seen vectors treated as 1-row matrices in any mathematical context. The fact that some frameworks use row-vectors and that there isn't that much difference in practice, doesn't give them a mathematical justification. But maybe the latter is not that important for you. | |
| Sep 19, 2011 at 22:38 | comment | added | user4513 | @Christian I guess Microsofts DX dev team is quirky then :P. | |
| Sep 19, 2011 at 22:12 | comment | added | Nathan Reed | I'm not sure what quaternions are gaining you here. You seem to be generating a matrix, converting it to a quaternion, and then converting it straight back to a matrix? Does the inversion issue still occur if you forget the quaternion and simply keep it as a matrix the whole time? BTW, @ChristianRau, row-vector convention is standard for some people, it's not "strange". :) | |
| Sep 19, 2011 at 21:58 | history | tweeted | twitter.com/#!/StackGameDev/status/115907741494673408 | ||
| Sep 19, 2011 at 21:43 | comment | added | Christian Rau | We sure need to know more of you transformation framework. Do you use matrix * column-vector convention or some strange row-vector * matrix convention? Maybe your Lookat function is intended for cameras and therefore does the inverse transformation to what you actually want. Also in a matrix*vector convention your combined transformation first translates the object and then rotates it. Is this even intended? | |
| Sep 19, 2011 at 20:54 | history | asked | Fabian | CC BY-SA 3.0 |