I am working on a project for a client where they want a package that is easy to edit for some video projects they are working on.
I have set up an expression on a comp to allow them to populate the text fields in the comp with names/dates that are attached from a .txt file.
My problem is, to make it truely dynamic I want to set the out point baised on how many names are in the .txt file.
So my question is: How do I set the out point of a comp with expressions?
Unfortunately, you can't change the work area's end point with expressions since they operate in layer properties and can't change Comp or Layer attributes outside the property they are applied to. Scripting, on the other hand, should allow you to do with what you want.
You can find the After Effects Scripting Guide in the After Effects Developer Center.
Also, the latest edition of Mark Christiansen's book After Effects Studio Techniques, includes a chapter on scripting by scripting guru/AE team member Jeff Almasol. I can't recommend this book enough.