Euler angles from Quaternion

Rhino Developer
1

Hi,

Does the SDK provide a method to convert a quaternion to euler angles?

Thanks,

-jelle

2

@greg, is this possible?

3

Actually, what I was looking for is the Roll, Pitch, Yaw from a Rotation || Quaternion.
I’ve come up with the following method, based on the .GetRPY() method found here

def rpy_from_quat(vX,vY,vZ, degrees=False):

data = [
    vX.x(), vX.y(), vX.z(),
    vY.x(), vY.y(), vY.z(),
    vZ.x(), vZ.y(), vZ.z(),
]

epsilon = 1E-12
pitch = math.atan2(-data[6], math.sqrt( (data[0]) ** (data[0]) + (data[3]**data[3]) ))
if math.fabs(pitch) > (M_PI / 2.0 - epsilon):
    yaw = math.atan2(-data[1], data[4])
    roll = 0.0
else:
    roll = math.atan2(data[7], data[8])
    yaw = math.atan2(data[3], data[0])

if degrees:
    return map(math.degrees, (roll, pitch, yaw))
else:
    return roll, pitch, yaw