Creating old-school Creature stop motion animation in Maya

6. The Stop-Motion Animation Process

6.2. Initial attempt on Stop-Motion in Maya

        I wanted to try and incorporate stop-motion and traditional computer animation together by showing a form of interaction between two characters. To achieve this I had to download another rig known as PjlHogan from a website called Mothermushroom. The model looked similar to a rudimentary robot. I then approached this scene by including some slap-stick comedy. In this particular scene the dinosaur approaches the robot character from behind unnoticed and scares it. As a result the robot is startled and stumbles. Timing became the primary issue to be resolved for this particular clip. I researched the web to find out how traditional stop-motion timing worked and came across these rudimentary guidelines.

1. Calculate the total running time of the stop motion animation scene you want to create. For the example, say the scene will be 3 minutes in length.
2. Convert the scene length to seconds by multiplying the minutes by 60. For this example, 3 minutes = 3 x 60 = 180 second.
3. Use a standard frame rate of 24 frames per second (fps). This is the traditional standard for stop motion animation. Calculate the total frames needed:
   180 seconds x 24 fps = 4320 frames
   No one said creating stop motion animation would be fast or easy.
4. Keep the flow of the motion consistent by setting some intermediate key-frames. Key-frames are important images in the animation sequence that help control story and timing. Stop motion animation, unlike hand drawn animation, typically lends itself better to frame to frame creation. The key-frame shots cannot be taken first, and the in-between shots taken later, although it may be possible with very careful arrangement and additional work when processing.
5. Break the animation segments into smaller animation scenes. For the 3 minute movie example, break out the sequence scene by scene to follow the storyline. If a 10 second scene is needed animating two object colliding together, there might be 3 key-frames:
   1. The first key-frame is the start of the scene where both objects are moving towards each other.
   2. The second key-frame is the objects just as they collide.
   3. The third key-frame is the deformation of the object just after the collision.
   4. The fourth animation key-frame is the motion of the objects heading away from each other.
   5. The fifth animation key-frame is the end of the scene.

        This 10 second stop motion clip would require 10 x 24 = 240 frames. To keep the scene timing smooth try keeping the key-frames about the same amount of frames apart. In this case, the key-frames would be about 60 frames apart. This is a much more manageable reference to use when moving object to get photographs. Animate the entire stop motion sequence to video.

Even though the above-mentioned instructions are quite useful for creating traditional stop-motion it was not recommended for what I was going to produce, hence I had to approach it in a different direction. When trying to keep keyed frames, every frame produces a smooth flow that finally ends up looking like traditional computer animation. The major drawback with this pathway was, since the animation itself was going to be computer generated the viewer will be able to identify and conceive that the end product is CG animation rather than Stop-motion.

       

Therefore I started looking for any clues on how to produce simple homemade stop-motion animations (for example Lego, clay stop-motion which are easily produced by many different people including kids in schools who are not even professionals in stop-motion) primarily because it has that easily conceived factor that its stop-motion. In one certain forum they mentioned that they used twelve keyed frames every second while in another CG forum (from Creative Cow) it mentioned that by changing the key-frames in Maya to "Stepped" rather than "besier", "linear" or other "ease-in/ease=out" key-frame types will produce that desired stop-motion effect.

Later I jumped into Maya and changed the Tangents → Default out tangent from Clamped (default setting) to Stepped in the Animation preferences in Maya. I started adding keys every twos thus making twelve keys per second. With Stepped the movement of each control does not show until the time slider reaches a key, as a result kind of shows that one frame pause which there is no key. On my first try I was concentrating more on the animation graph editor, trying to match every key to produce arcs and bends, similar to how it looks in traditional computer animations.

After animating the dinosaur to 260 frames, I then recognized that the dinosaur was showing some offset (motion wise) compared to the usual animation of the robot, but was not showing the desired stop-motion characteristic. The reason on why it was appearing smooth was because I went around animating the dinosaur in accordance with traditional computer animation using key-frames and the graph editor. For example, adding key-frames to a leg for the start and end poses then doing the in-betweens was one reason why the animation didn’t yield the desired result. The above-mentioned methods proved catastrophic and I had to go back to the drawing board to redesign the entire scene as well as try and correct the flaw.

         
My next attempt was to obtain a script which could modify the animation that I had already created to make it appear jerky. I found a Mel script called Jitter Bug 2.5.0 which added non-destructive controllable random jitter to keyed objects based on user settings. Using this script it was possible to remove the jitter or swap it with the original animation curve at any time. There were many options included in the script that enabled random or non-random offset and drop-off. There was also a mode that simulated a stop motion feel by basing the amount of random jitter on the speed of the object or control. To yield the proper results I simply had to select the keys that I wanted to jitter and run the code. This resulted in a GUI popping up which contained a graph editor. Initially the controls in the GUI were formidable and confounding. Nevertheless I gave it a try, and even though it produced the jerky animation I was aiming for, it also did produce some awkward movements on certain instances (when the dinosaur was stationary) since it was randomizing each key to different extents.

 

Graph editor showing the "Stepped" curves, The curves look similar to "Clamped" thus producing smooth animation.

                          First attempt on creating stop-motion in Maya. You can see some difference in the motion between the Dinosaur (bit slower) and the Robot.

Jitter bug GUI used for the project.

Jitter Bug GUI (obtained from the website) and the modification it produces on smooth curves. 
 

 

Top : Previous graph for the "Torso" control, Bottom : After using the "Jitter Bug" mel script. Key frames are added every two frames also randomizing the offset.

                                                                   The use of "Jitter Bug" gave a weird constant vibration to the animation.---> The use of Jitter Bug produced an unwanted constant vibration to the animation.