So here's my latest and greatest quick tip for you:
If you are trying to copy and paste a path from Adobe Illustrator into Adobe After Effects, and you would like to use that path as a motion path, the original path cannot have any fill or stroke applied before you copy it. If it does, even if you paste it into a position or path attribute, it will turn into a mask (or possibly many masks, if you have a dashed stroke).
If you didn't understand the above paragraph, here's the basic situation:
- You would like something to move along a path in After Effects, but you have the path stored elsewhere (likely in Illustrator).
- This is normally simple - you go into Illustrator, use the Selection tool to select the path, press Ctrl+C to copy. Go into After Effects and click on the Position attribute of the thing you want to move, and press Ctrl+V to paste. A keyframe should appear where your cursor was. To expand this, hold down Alt and drag the keyframe out to the right.
- Unfortunately, if your original path in Illustrator had a fill or a stroke applied, AE will interpret this as a mask - possibly many of them - rather than a stroke. You will be able to see the path, but it will be in bright green, meaning it's a mask. Position paths appear in light purple.
- Solution: just make sure you have the bare path selected before you copy/paste across programs.
Did this help you? Have any other ideas for how to accomplish the same thing? Let me know!