Tuesday, September 17, 2013



Momentum! aka INERTIA

      Always remember my advice and views are just one possibility. Chocolate might not be the best ingredient for every cake... This post is less of a lecture but more of a bunch of tips put together that have helped me out over the years. 

     When animating things move you must establish a force. Ask yourself: what is making this object/body-part move? Can you 'see' that visually?
For example: if you are observing a body is walking across the screen you could ask yourself: what is making it move? You answer: The legs. Can you see it? Are the legs moving the body realistically?.....

     Believable Animation always dies when things move for just the hell of it. When your object moves realistically, the viewer then has the freedom to observe the story/character instead of wasting time figuring out why the animation looks so weird.

small ball vs. BIG BALL
     Heavy objects take longer to accelerate and decelerate but they can move just as fast as anything else. (the ease in and ease out will just take more frames!)
      Now for CG animators we have to translate this knowledge into the all mighty graph editor (DUN Dun dun) That might sound like a scary task so I made a cheat sheet for you. Some teachers might just say, go explore the graph editor and figure it out for yourself. Why waste your time when i have the answers right here. Leonardo Davinci would have his students copy to learn! And they all ended up as great accomplished painters in their time.
      Below check out how the small ball has short ease in and ease outs. Smaller things usually have less mass which equals less momentum when it's moving around. Heavy objects will have longer ease in ease outs.
On the left is the graph editor for the small ball and the right side has the graph editor for the heavy ball. 
-Make sure anything pulling something heavy has a 'straight' line in it
-In a walk cycle: heavy spends more time at the bottom

The Balloon Exercise 
-will challenge you to: animate something light with little momentum, perfect your bouncing ball skills by forcing you to animate the same pattern upside down. Animate a ballon bouncing across the ceiling!

Remember this is just like a bouncing ball but upside down. 

         When looking at your animation you should be able to pause it and still see what direction the momentum is going in the object that is moving. Moving your characters and objects around isn't the whole story. You must construct appealing shapes that communicate where the momentum is going. The silhouette can say so much about what direction your object is going.

You should always tell where the mass is at in soft objects. 
-Just in case I didn't make it clear enough, here are the definitions of the concepts I am typing about.

MOMENTUM from wikipedia
In classical mechanicslinear momentum or translational momentum (pl. momenta; SI unit kg m/s, or equivalently, N s) is the product of the mass and velocity of an object. For example, a heavy truck moving fast has a large momentum—it takes a large and prolonged force to get the truck up to this speed, and it takes a large and prolonged force to bring it to a stop afterwards. If the truck were lighter, or moving more slowly, then it would have less momentum.

Issac Newton on INERTIA
"The vis insita, or innate force of matter, is a power of resisting by which every body, as much as in it lies, endeavors to preserve its present state, whether it be of rest or of moving uniformly forward in a straight line."

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