Re-rendering a portion of an image

摘要

An image may be represented by a directed acyclic graph (DAG) including a number of nodes on paths between input parameters and output values. Intermediate operations are performed at the nodes to produce intermediate output values. One or more of the input parameters may be modified (e.g., by an animator). A determination is then made as to which intermediate output values are affected by the modified input parameters. A simplified DAG is constructed from the nodes corresponding to the intermediate output values affected by the modified input parameters. The intermediate output values that are not affected by the modified input parameters and are maintained at a constant value corresponding to a previously determined value for the intermediate output value. The simplified DAG is evaluated to determine the output resulting from the modified input parameter such that the image may be re-rendered without re-evaluating the full DAG.