This article will show designers, architects, and engineers how to make more appealing animations for visualization, architecture, and design. I’ll take the basic principles of animation and use them to demonstrate ways to make your animations more visually appealing and easier to understand. I’ll cover such topics as design and layout, and the importance of storytelling and maintaining proper timing. I’ll also cover technical topics such as animation curves, motion paths, and rigging, but in a non-software-specific way to make the topics and processes accessible to all.
I. Animation Starts with Images
Animation starts with a collection of images that tell a story. Getting these images right is the first step to making engaging animation.
Good Composition and Design
Start with a good composition that highlights the key story point for that scene. Check your camera angles, and understand the before/after shots as well. Always ask yourself, “What story point do we need to communicate here?”
The layout is the organization of your “set.” Make sure you have enough room for the intended action to happen.
Staging is how the action proceeds within the layout. Make the key elements of the scene stand out so that the audience’s eye is drawn to them. Subtly telling the audience where to ‘look’ is an important part of staging.
Key elements should look good in silhouette. Remember, people see outlines first, and then fill in the details. If the silhouette is confusing, it will take longer for the shot to “read.”
Multiple shots require continuity between shots. Understand basic film language (long shot, medium, close up, etc.). Understand the concept of screen direction. Be sure to do hook-ups across cuts, etc. Storyboards help!
II. Basic Principles of Motion
Animation is what brings the scene to life. In character animation, we bring characters to life, but the same principles apply to anything that is animated. We’ll focus on the laws of motion as they apply to non-character-related scenes.
It’s Really Just Physics
The Principles of Motion for animation are simply derivations of Newton’s laws of motion (i.e., F=ma). These have been boiled down into some rules of thumb that animators use to simulate reality. Remember, animation is the animator’s interpretation of reality, not reality itself.
As things move, they typically “slow-in” to the start of the motion and “slow-out” at the end of the motion. This is really just the result of forces acting on the object. In some cases, things stop suddenly, but these are exceptions.
In nature, most things move along arcs. For things moving freely, this is an extension of the slow-in/slow-out concept. Forces slow an object along one axis, giving the appearance of an arc. In connected assemblies, such as joints, the end points of these assemblies tend to follow arcs.
Overlap and Follow Through
Not everything in a scene moves at the same time, and this principle applies mostly to assemblies of objects. Motions can overlap when an object is in motion, so parts of the assembly may overlaps the main motion of the object. When an object or assembly comes to rest, some parts of the assembly may “follow through,” where they continue the motion for a few frames, then settle into a stop. This is sometimes called “secondary motion.”
This is basically the concept of friction as applied to animation, and is similar to overlap and follow through. A force does not affect an entire assembly at once. The motion of some parts may “drag” behind the others due to this.
In some ways, this is more of a character animation principle, but it can be used to good effect in other types of animation. Anticipation is moving something in the opposite way for a few frames before it moves in the intended direction (i.e., raising the hand before hitting the table). This little trick can draw the audience’s eye to an object before it starts moving.
Timing makes the scene flow smoothly and keeps the audience engaged. This is probably the most subjective of the principles. Good timing is felt more than seen, and it can have strong roots in other time-based art forms, such as music. There are many ways to develop a good sense of timing. Music helps a lot, as does watching other animation to see what works.
Animation in a CGI application happens mostly through keyframing. The keyframe records the position (or other important attributes) of an object at a specific point in time. Multiple keyframes change the attribute though time.
Block It out. Then Refine.
The best way to animate with keys is to do repeated passes over the animation. The first pass is typically called a blocking pass, which keys just the major points of the motion. After that, the timing of the blocking pass is refined, new keys are added (if needed) and the process repeats.
Make Your Curves Matter to Reduce Number of Keys
During the animation process, the animator may need to adjust timing. This can be done by either adding keys or by refining the curves. The rule of thumb is to adjust curves first, since it keeps the timeline free of extra keys. Too many keys can create headaches when revisions happen. A cleaner timeline makes adjusting the overall animation an easier process.
Use Your Tangents
There are several types of tangents, and these will vary depending on the software used. These can include, Bezier, linear, and stepped, among others. Understand your options and use them well.
Another way to create motion is to use a motion path. Typically, this is a spline or a curve that is placed in the scene. A motion path can be a good alternative to pure keyframing in that the motion curve defines the motion of the object through space.
Creating Motion Paths
The motion path is typically followed by the object’s pivot point, so take that into account when drawing paths. Alternatively, you can link the object to a helper object which, in turn, is controlled by the motion path.
One common problem with motion paths is maintaining velocity. Sometimes adjustment of a motion path can lead to your object speeding up or slowing down, so be sure to understand your software.
Using Keys on Motion Paths
Another way to control motion is to add keyframes to an object controlled by a motion path. Typically, this key represents a percentage of the total curve, so as the curve is adjusted, the relative positions may change.
One more way to control objects is to rig them. A rig can be as simple as a hierarchy, but it can also extend to other tools such as constraints, joint chains, and deformations, all the way up to script and expression-based automation. A good rig makes logical connections between objects in a system and speeds the animation process.
Hierarchies are the simplest way to connect the motion of objects together. You can use them to connect objects directly, or you can use helper objects/nodes to create additional points of control for a single object.
Constraints typically tie two similar attributes together so that object motion can be controlled more easily. An object can have its attributes tied to the attributes of one or more other objects. These attributes can be anything from position, rotation, and scale, to other attributes such as hierarchical links.
Joints and Inverse Kinematics
Joints are basically just another type of hierarchy. Typically, these simulate the bones of a character, but they can be used in a variety of non-character animation-related tasks. Forward Kinematics (FK) is where a joint chain is manipulated via rotation. Inverse Kinematics (IK) introduces the concept of a “goal,” where the joint chain rotates automatically to touch the goal. Moving the IK goal via translation automatically rotates the joints.
Not every object is rigid. Deformations allow for an object’s shape to change and animate. Deformations can be controlled by joint chains, but can also be controlled parametrically using such tools as bends, lattices, and waveforms.
Scripting and Expressions
In more complex rigs, scripts and expressions can be used to algorithmically create motion, or animate an object in relation to another.
As you can see, the animation process can be simple or complex, depending on the needs of the project. Regardless of the complexity of the process, the basic goal is to simply create high quality images that tell a story. Above all, animation is a communication medium, so be sure to keep this in mind as you create your own projects.
George Maestri is an animation industry professional with extensive experience as a writer, director, and producer, working on a number of hit television shows, including “South Park” and “Rocko’s Modern Life.” As an entrepreneur, he built a successful studio that produced several hundred cartoons for broadcast, education, and film. George has written over a dozen books on animation. As an educator, he has taught at several top animation schools, including California Institute of the Arts.