Simple Mover C4D Python Expression Tag

SimpleMover.py

"""Name-US: Simple Mover
Description-US: Expression Tag that Moves and Object Over Time

Version History
===============

v0.0.1 - Initial Version

Copyright (C) 2018 Maxon Computer Inc.
Written for Cineversity.com
Written by Donovan Keith <donovanskeith@gmail.com>
"""

import c4d

def GetValueAtTime(start, rate, time, offset=0.0):
    """Calculates PSR for rate at time. If vector is 0
    for a given channel (XYZ, HPB), then start will be returned."""
    
    value_at_time = start
    if rate.x:
        value_at_time.x = rate.x * time + offset
    if rate.y:
        value_at_time.y = rate.y * time + offset
    if rate.z:
        value_at_time.z = rate.z * time + offset
        
    return value_at_time

def main():
    obj = op.GetObject()
    if obj is None:
        return
    
    # Get a direction/trajectory from the user
    move = op[c4d.ID_USERDATA,1]
    rotate = op[c4d.ID_USERDATA,2]
    scale = op[c4d.ID_USERDATA,3]
    
    # Get the time in seconds
    time = doc.GetTime().Get()
    
    # Position
    start_pos = obj.GetRelPos()
    new_pos = GetValueAtTime(start_pos, move, time)
    obj.SetRelPos(new_pos)
    
    # Scale
    start_scale = obj.GetRelScale()
    default_scale = 1.0  #Don't start from 0 scale.
    new_scale = GetValueAtTime(start_scale, scale, time, offset=default_scale)
    obj.SetRelScale(new_scale)
    
    # Rotation
    start_rot = obj.GetRelRot()
    new_rot = GetValueAtTime(start_rot, rotate, time)
    obj.SetRelRot(new_rot)