Mean Rotation, object filps 180

Helper

On 16/07/2014 at 23:48, xxxxxxxx wrote:

Could some one please help me with why the object keeps flipping around to -180 when finding the mean rotation between two objects and how I could prevent it?

import c4d
from c4d import utils
  
def SetGlobalRotation(obj, rot) :
    m = obj.GetMg()
    pos = m.off
    scale = c4d.Vector( m.v1.GetLength(),
                        m.v2.GetLength(),
                        m.v3.GetLength())
  
    m = utils.HPBToMatrix(rot)
  
    m.off = pos
    m.v1 = m.v1.GetNormalized() * scale.x
    m.v2 = m.v2.GetNormalized() * scale.y
    m.v3 = m.v3.GetNormalized() * scale.z
  
    obj.SetMg(m)
  
def main() :
    a = op[c4d.ID_USERDATA,1]
    b = op[c4d.ID_USERDATA,2]
    c = op[c4d.ID_USERDATA,3]
    
    aRot = utils.MatrixToHPB(a.GetMg())
    bRot = utils.MatrixToHPB(b.GetMg())
    cRot = utils.MatrixToHPB(c.GetMg())
    
    x = [aRot,bRot]
    mean_rot = sum(x)/2
    SetGlobalRotation(c, mean_rot)

https://dl.dropboxusercontent.com/u/2802779/mean_rotation.c4d