View Full Version : <transform>.getRot() not working

12-03-2003, 05:23 PM
I noticed the function getRot() is not consistent.

I got the following lines in the interactive window:
>>> import vizmat
>>> X = vizmat.Transform()
>>> X.makeRot(0,1,0,180)
>>> X.getRot()
[0.0, -1.0, 0.0, 180.00000500895632]
>>> X.makeRot(0,1,0,90)
>>> X.getRot()
[-0.70710670948028564, 0.0, 0.7071068286895752, 180.00000500895632]

Could someone help out here?


12-04-2003, 11:35 AM
Hi David,

The makeRot function sets the 4x4 matrix to represent the given axis angle rotation. Since there are many ways to represent a rotation the rotation returned might not always be exactly the same as the one given. [0,1,0,180] is the same as [0,-1,0,180], even though they don't look the same.

However your second example isn't correct and I believe we have fixed that problem. If you like, i can send you a patch for it, otherwise you'll have to wait for the next release.