The core concept of Inventor is the scene graph. A scene graph is a directed acyclic graph where each node effects the nodes to the right of it and below it. Each of the nodes in the graph represent a system object, which may be a shape, an appearance characteristic, a transformation, a camera, or a light. 3-D scenes are created by organizing the nodes in the scene graph so that they inherit the correct characteristics. In the text below, "the nodes after node A" refers to all of the nodes to the right of node A and below node A in the scene graph.