- Dependency – As a graph of connections between nodes. This shows which nodes provide input or output to other nodes.
- Hierarchy – As a hierarchical list of nodes. This shows which nodes are parents and children of other nodes.
Dependency graph
The dependency graph is one of two ways Maya represents your scene . It’s a chain of nodes. The dependency graph is like a series of instructions for how to get the current scene starting from scratch: “create a sphere A, move these CVs, create a curve B, project curve B onto sphere A to create curve-on-surface C, trim sphere A using curve on surface C”, and so on.
The dependency graph gets its name from the connections between nodes. In the example above, the project curve operation depends on two inputs: sphere A and curve B.
Each node in the dependency graph represents an action to build up or change the scene, with the final result being the scene in its current state.
What this lets you do is modify or reshape input objects, change attributes on a node, change node connections, or delete nodes, and have Maya automatically and instantaneously update the entire scene to reflect the changes.
The connections between creation and editing nodes is also called construction history, because it records the history of how the scene was constructed.
You can view and edit the dependency graph in the Hypergraph.
For any particular node, the dependency graph shows the node’s history. The node’s history includes all the nodes that are connected to it, or are connected to nodes that are connected to it, and so on. For discussing a node’s history, the terms input and output connections can be useful. Input nodes are nodes that can be evaluated before the node itself is evaluated, and Output nodes are nodes that can be evaluated only after the node itself is evaluated. Note that, from Maya’s perspective, a node’s history includes its future as well as its past.
Scene hierarchy
The scene hierarchy is the grouping of child nodes under parent nodes. While you could create a scene without establishing a hierarchy, you will find that it makes modeling and especially animation much easier. You can view and edit the scene hierarchy with the Outliner or the Hypergraph.
In general, the arrangement of parent-child relationships for all connected nodes that make up an object (also known as object hierarchy) or a scene (also known as DAG or scene hierarchy).
