Maths - Quaternion to AxisAngle - Error Report

By: nobody ( Nobody/Anonymous )
Error in Quaternion to AxisAngle
2003-01-27 15:25
Hi,

I think that you have an error in you Quaternion to AxisAngle derivation... Your code is right, but in the derivation, you are not doing the samething as in the proof! :-(

I think the bug came from the page AxisAngle to Quaternion... where the code is wrong (at least, if you look at your definition of quaternions)!! You should have ('multiply s' instead of 'divide by s'):

double s = Math.sin(a1.angle/2);
x = a1.x * s; y = a1.y * s; z = a1.z * s; w = Math.cos(a1.angle/2);

Alexis

By: martinbaker ( Martin Baker )
RE: Error in Quaternion to AxisAngle
2003-01-27 16:53
Alexis,

Thank you very much for letting me know about this, I have corrected it as you suggested.

Martin