GoJS offers several built-in animations, enabled by default, as well as the ability to create arbitrary animations.
The Diagram.animationManager handles animations within a Diagram. The AnimationManager automatically sets up and dispatches default animations, and has properties to customize and disable them. Custom animations are possible by creating instances of Animation or AnimationTrigger. More information can be found in the GoJS Intro.
The GoJS Geometry class controls the "shape" of a Shape, whereas the Shape.fill and Shape.stroke and other shape properties control the colors and appearance of the shape. For common shape figures, there are predefined geometries that can be used by setting Shape.figure. However one can also define custom geometries.
One can construct any Geometry by allocating and initializing a Geometry of at least one PathFigure holding some PathSegments. But you may find that using the string representation of a Geometry is easier to write and save in a database. Use the static method Geometry.parse or the Shape.geometryString property to transform a geometry path string into a Geometry object.
More information can be found in the GoJS Intro.