I realised that the values go wrong because before the decompose I multiply the matrix basis with axis_change which is:
axis_change = mathutils.Matrix( ((1.0, 0.0, 0.0, 0.0), (0.0, 0.0, 1.0, 0.0), (0.0, -1.0, 0.0, 0.0), (0.0, 0.0, 0.0, 1.0))
is there a way to change the axis order without causing the broken values ? —
Vettel.Sebastian Jul 14 at 14:29