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@ivogrig ivogrig/
Last active Sep 30, 2015

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Example method for turning a direction vector into an euler rotation (TD SDK)
# python
# Example method for turning a direction vector into an euler rotation
# There is a similar example using the API for this by Lukasz Pazera:
# This function really does the same, using the mathutils of the TD SDK
import modo
import math
def lookAt( directionVector = modo.Vector3(1,0,0),
upVector = modo.Vector3(0,1,0),
axes = 'xyz',
rotOrder = 'zxy',
asDegrees = True,
offsetMatrix = None):
'''Retuns an euler rotation with x aligned to the given direction vector and y to the optional up vector.
:param Vector3 directionVector: Direction to aim at
:param Vector3 upVector: Direction the twist of the rotation should aim at (what is considered up)
:param basestring rotOrder: Rotation order to use for the resulting euler rotation.
:param bool asDegrees: Outputs the rotation as degrees if True, as radians otherwise.
:param Matrix4 offsetMatrix: By default x will point in the direction and y is up. This rotational offset matrix can be used to adjust the axes
# Get up and normal vectors perpendicular to the direction vector by crossing
normalVector = directionVector.cross(upVector).normal()
upVector = normalVector.cross( directionVector ).normal()
# Create a transformation matrix from the three vectors
matrix = modo.Matrix4( (directionVector.values, upVector.values, normalVector.values) )
# Apply offset matrix in
matrix = offsetMatrix * matrix
# Return as euler rotation values
return matrix.asEuler(degrees=asDegrees, order=rotOrder)
# Example usage, creating locators:
scene = modo.Scene()
directionVector = modo.Vector3( 0.123, 0.456, 0.789 )
directionLocator = scene.addItem('locator', name='Direction')
upVector = modo.Vector3(0.34, -0.84, -0.16)
upVectorLocator = scene.addItem('locator', name='UpVector')
rotationLocator = scene.addItem('locator', name='Result')
# This method is only available in 901 SP3
#offsetMatrix = modo.Matrix4.fromEuler((0,math.radians(90.0),0))
# ... so I use a quaternion to create the matrix instead now to offset the rotation
# so that -Z points to the given direction
quat = modo.Quaternion()
quat.setAxisAngle( (0,1,0), math.radians(90.0) )
offsetMatrix = quat.toMatrix4()
eulerRotation = lookAt(directionVector, upVector, axes='yxz', offsetMatrix=offsetMatrix)
rotationLocator.rotation.set( eulerRotation, degrees=True)
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