I posted this question in the animation forums but thought it may be of discussion quality in the general forums as well. When creating animations for objects that have more than one animating element. Do you put all the animations into one animation or do you tend to create individual animations and key frame-chain them together? Example: I have an animation on a door that has a separate handle mesh so I can also animated that separate from the door. My initial animation has the door handle animating from key frame 0-10 (rotates on it Y-axis to 30 degrees and back to 0 degrees) and the door animates from key frame ~5-60 (which rotates it 90 degrees on its-Y axis) when it is opening. So the illusion look like the player turned the handle and opened the door. However this than requires me to create a separate door animation called door_closing which animates the door from the open state (Y-axis 90 degrees) to the closed state( Y-axis 0 degrees) without the handle moving. So I have for each type of door three animations door_opening, door_closing, door_locked. The door locked animation simply attempts to rotate the door handle only a few degrees back and forth for about 60 frames. Basically it goes from 0 degrees to about 12 degrees and back again and it does this 4 times. So Key Frame 0-10 rotates 12 degrees. Key Frame 10-20 rotates back to 0 degrees. It does this on Key Frames 20 - 30, 30 - 40, 40 - 50, 50 - 60. This works fine in all tests; but now I am trying to determine now if this is the best practice approach or is it better to create an animation file by element and have them keyed by their frames in a chain event structure. So I create an animation for the door handle called turn_handle and it goes from key frame 0-10 rotating the handle 30 degrees on its Y-axis than back to 0 degrees. There is also a door animation called open_door that starts from key frame 8 with door position 0 but goes from 8-60 rotating the door 90 degrees on its Y-axis. So when the player triggers the door animations it calls for turn_handle and open_door and they play simultaneously with their key frames being properly timed together giving the proper illusion to the player. In this way I can simply reverse the animation speed from 1.0 to -1.0 on the open_door and it "closes" the door. In this fashion (I haven't implemented it yet but will test it), I would have only 2 animations, turn_handle and rotate_door. When the door is locked I play the turn handle animation from key frame 10-60 with the audio file for locked door, while Key Frame 0 - 10 rotates the handle by say 28 degrees and back to 0; or what ever frame rate I need to go with for aesthetic purposes. So how do you approach such things (whether it is a door, car, machine, monster, weapons, etc.)? What is your take on these two approaches? Do you use animations or simple quaternions and math for this?