Script nodes are a way of storing a MEL script in a Maya scene file.
You can set a script node to execute its “payload” in response to various events:
- When the node is read from a file.
- Before or after rendering a frame.
- Before or after rendering an animation.
- When a file is closed or de-referenced.
A script node has three attributes: Before, After, and Type. Depending on the Type of script, the Before and After attributes specify when the script executes.