The leaf nodes in a scene graph contain objects that are rendered into the scene or that participate in the rendering of the scene. Leaf nodes can be one of the following objects:
Geometric primitives: geometric lines, curves, or surfaces that represent the building blocks of a virtual environment. Each primitive is enriched with three types of properties:
material properties and possible textures that are combined with lighting to compute the pixel colors,
sonic properties that produce spatialized sounds associated with primitives,
and physical properties for managing collisions and object cinematics.
Lights: lights are necessary to render a scene, there is no default lighting in VC.
Viewpoints: in addition to a default viewpoint located at the origin, several viewpoints can be added to a scene at various locations in the scene graph. They are particularly useful for animation films with multiple cuts in the same scene.
Crowds: crowds are used to render collective behaviors with displacements driven by goals and restricted by obstacles and agent interactions.
Graphs: graphs are used to modelize and render the motion of sets of masses connected by springs in a non-directed graph structure.