[Jeff Almasol]

Scott,

Note that blendingMode and trackMatteType are attribute of the AVLayer object (accessed as .blendingMode and .trackMatteType from your layer variable), but BlendingMode.ADD and TrackMatteType.ALPHA are enumerated values that you either assign to these attributes or retrieve from them. Their names (TrackMatteType vs. trackMatteType) are similar, but their usage is not defined by whether it’s initially capitalized or not. The enumerated value could’ve just as easily been defined as myTrackMatteTypes.ALPHA, it’s just a similar name and initial cap syntax was used to make the association with the attribute that would use it.

Jeff

[Jeff Almasol]

Hi Scott,

You need to use TrackMatteType.ALPHA (note the initial capital T), which should be how it’s listed in the doc.

Your blendingMode.ADD example doesn’t work for me (I get a “blendingMode is undefined” message). Maybe you have a blendingMode variable earlier in your script?

Jeff

[Jeff Almasol]

Hi Scott,

I’m not sure I follow how the second procedure is the same as the first. The precompose() method occurs in the context of a comp, so if you’re precomposing the selected layer, the selected layer becomes a precomp layer. So if you’re precomposing the original precomp A (the precomp layer in the original comp), comp B is now in the original comp. Then, if you’re repeating to create C, are you precomping the precomp A layer which is now in comp B?

In any case, I think I’d go with your first procedure. Seems clearer to me, and also supports the ability to add layers to comps that don’t have the same dimensions, durations, and pixel aspects, which may or may not be important in your scenario. If I’m misunderstanding your second procedure, if it just shaves off a statement or two but might be difficult to debug/follow at some later date, it’s not worth it to me. YMMV.

Jeff

[Jeff Almasol]

If you’re using AE 7, one solution is to use my rd: Render Layers script for rendering selected layers separately. You can find it here:
https://www.redefinery.com/ae/view.php?item=rd_RenderLayers

Jeff