# Scene Graph ## What is a scene graph? From wikipedia... A scene graph is a collection of nodes in a graph or tree structure. A node may have many children but often only a single parent, with the effect of a parent applied to all its child nodes; an operation performed on a group automatically propagates its effect to all of its members. In many programs, associating a geometrical transformation matrix (see also transformation and matrix) at each group level and concatenating such matrices together is an efficient and natural way to process such operations. A common feature, for instance, is the ability to group related shapes/objects into a compound object that can then be moved, transformed, selected, etc. as easily as a single object. ### How does this relate to the Dali public API? Actors are effectively nodes that receive input (touch events) and act as a container for draw-able elements (which are also nodes) and other actors.