Pass & Return Values from a Container
Using Property Sets Before and After is analogous to passing parameters to, and returning values from, a function, where the container is the “function”.
- The Property Sets Before tab allows you to pass values into the container by setting some of its Custom and/or System Properties. This is analogous to the “input” parameters of a function.
- The Property Sets After tab allows you to extract values from any of the container’s Custom or System Properties and place them into some other properties. This is analogous to the “output” parameters and/or “return value” of a function.
A common case uses a nested Clip from inside of another Clip. The nested Clip can be considered as a “function”, and the containing Clip can be considered as the “caller”. The container wishes to pass values into the nested Clip to alter its behavior, and the nested Clip wishes to return values back to its caller.
When you design a Clip with the intent that it will be nested inside of other Clips, you might want to design the Custom Properties of your nested Clip with this feature in mind. Consider any behavior that the user of the nested Clip might need to alter, and create a Custom Property that the user of the nested Clip can set to cause that alteration. In addition, consider any output information that the user of the nested Clip might want, and arrange to place such information into Custom Properties during the play of the Clip. You might even consider adopting a naming standard for the Custom Properties of your Clips so that users of the Clips know what the Custom Properties are for, and which ones are “inputs” and which ones are “outputs”.