SE3.Eul() method returns same for 180 degree rotation about X and Z axes

bdaiinstitute / spatialmath-python

Create, manipulate and convert representations of position and orientation in 2D or 3D using Python

MIT License

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SE3.Eul() method returns same for 180 degree rotation about X and Z axes #45

Closed jmount1992 closed 2 years ago

jmount1992 commented 2 years ago

The SE3.Eul method returns the same matrix for a 180 degree rotation about the X and Z axes.

Running

import spatialmath as sm
print(sm.SE3.Eul([0, 0, 180], unit='deg')) # this creates same rotation matrix as line below
print(sm.SE3.Eul([180, 0, 0], unit='deg'))

Haven't had a chance to look further as to why. Will hopefully find the root of the problem and do a PR.

petercorke commented 2 years ago

This is correct behaviour. Because the middle rotation is zero, it is a rotation of 180deg about z-axis in both cases.