Lecture 4

Lessons from Traditional Animation 2

contains images from

www.pixar.com

www.odyssey3d.com

Lasseter, John "Principles of Traditional Animation Applied to 3D Computer Animation," Proceedings of SIGGRAPH '87, Anaheim CA, pp. 35-44 - available in the EVL Library. Please read the paper before coming to class.

• Squash and Stretch - Define rigidity and mass of object by distorting its shape during action
• Timing - Define weight and size of objects / personality of characters by spacing actions
• Anticipation - The preparation for an action
• Staging - Presenting an idea so it is clear
• Follow Through and Overlapping Action - Termination of an action and establishing its relationship to the next action
• Straight-Ahead Action and Pose-To-Pose Action - Two contrasting appreached to creating movement
• Slow In and Out - Spacing of inbetween frames to achieve subtlety of timing and movement
• Arcs - The visual path of action for natural movement
• Exaggeration - Accentuating the essence of an idea via the design and the action
• Secondary Action - The action of an object resulting from another action
• Appeal - Creating a design or an action that the audience enjoys watching

Squash and Stretch

• rigid objects retain shape during movement
• living flesh deforms
• volume remains constant
• hinged objects like luxo folds and extends
• very important for faces to suggest the underlying muscles
• stretch is useful to ensure object positions overlap when object moving quickly

Timing

• spend enough (but not too much) on preparation, action, reaction - too much time and audience's attention will wander, too little and the audience wont understand what happened
• determines weight of object - more massive objects require more force to start / stop / change motion
• weight depends on spacing/timing of poses, not the poses itself
• realism of an object depends on how it looks and moves
• example from paper of 2 face positions with 1 to 10 in-between frames

Anticipation

• living creatures must prepare before executing an action - walking starts with hips - the hips lead the legs, eyes lead the head
• prepare the audience for the action that is coming
• draw the audience's attention to the right place - then the action can be faster

Staging

• action staged to be understood, personality to be recognizable, expression to be seen, mood to affect the audience
• audience should only see one idea at a time
• in a still scene audience attracted to movement, in a busy seen eye attracted to stillness
• better to show action in silhouette

Follow Through and Overlapping Action

• appendages and loose parts of an object or character drag behind the leading parts
• heavier objects take longer to come to a stop
• people seldom complete one action before starting the next

Straight Ahead Action vs Pose-to-Pose Action

• straight ahead is more spontaneous, more creative
• pose-to-pose is more planned out where timing is important
• with computer animation the computer may not do well in interpolating the inbetweening - better to work top down through the hierarchy

Slow In and Out

• increase the expressiveness of the keyframe poses by timing the inbetweens so there are more towards the beginning and ending of a motion rather than equally spacing the inbetween frames between the two extremes.

Arcs

• straight-line paths look stiff
• arcs show the most economical route
• with computer animation the inbetween frames may follow straight lines - may need to add a curve too it to make it more realistic

Exaggeration

• exaggerate for enhancement of the key idea to make it easier for the audience to understand
• dont want the exageration to be too excessive
• need to keep parts of the scene 'normal' so the exageration stands out

Secondary Action

• highlights interest and adds realistic complexity
• facial expressions can be a secondary action - it will be missed if it occurs during a movement

Appeal

• pleasing design and movement
• avoid twins - both arms or legs or sides of the face in the same position

Show Luxo Jr. (1986) and The Adventures of Andre and Wally B. (1984) to complement the paper

Coming Next Time

General Physics

Please read the 4 pdf files before coming to class next Tuesday