convert a AI layer into a mask

The easiest way to create a mask from any layer that has transparency is to use the layer as a Track Matte or as the source for the Set Matte effect applied to another layer. Let us know if you have any questions about those workflows.

 

If you have adequately prepared your Illustrator file for use in video production, and you have the objects you want to convert to masks on separate layers with no strokes applied and only solid color fils, you can convert the Vector file to a Shape layer. You can then select the path and copy it. I always just set a keyframe and copy or cut the keyframe because then I know for sure that I copied the path.

 

You can paste that path to a motion path or another layer as a mask by selecting the pen tool, clicking anywhere to start a mask, and then pasting, but there is a catch. A shape layer's Anchor Point is at 0, 0, no matter the comp size. It's the same for a text layer. The Anchor point for an Illustrator layer (Vector Layer) is always at the layer center. If you imported the AI file as a comp and did not retain layer size, the anchor point will be at the comp center. When you convert a vector layer to a shape layer, the anchor point will not be reset to 0, 0. It will still be in the same place before you converted the layer. If you check the values, you can reposition the layer to get the mask to line up, or you can add a null to the timeline, parent the layer to the null, then reset the null's position to 0, 0 to get things lined back up. 

 

As my friend angie_taylor said, you can copy a path in Illustrator and paste it directly to a layer in After Effects if you start with the pen tool, but you have to ensure that the AI file is properly prepared for that to work accurately also. The artboard must be the same size as the Composition, and there are a few other things that can foul things up, but it is a way to get a path from Illustrator to After Effects very quickly.

 

I rarely do what you are trying to do, but I  often use AI or other layers as track mattes or as a source for Set Matte. It's painless, renders quickly, and doesn't cause any headaches.  You might have to pre-compose to use Set Matte, but it is all still straightforward.

Instead of opening the AI file in AE, just copy and paste the path from
Illustrator into After Effects. In order to do this, go to the preferences
in Illustrator and go to Files and Clipboard prefs. In here select AICB and
choose the option to Preserve Paths.

You should now be able to copy the path in AI and then Paste it in AE.

cheers,

Angie Taylor