How can I create Motion titles with fixed-length transitions? I'm using Motion to create text overlays for a video that I'm editing in Final Cut Pro X. Each time an overlay appears on the video, it uses a transition to slide into view and to slide out again when finished. I've created a custom title in Motion that behaves as follows: the text is visible for 7 seconds, with a transition lasting 10 frames at the start and end.

Here's my problem: sometimes I want the text to be visible for a different duration. If I add my custom title to the FCPX timeline, then change the duration of the title from 7 seconds to 14 seconds, the transitions take twice as long to complete. It looks silly! Is there any way that I can make a title whose start/end animation takes place over a fixed duration, but where the total duration of the title can be customized freely?
You can use Build-In and Build-Out markers. If you right click (or control-click) on the top of the timeline, you'll get a pop-up menu with an option to add a marker. When you add it, you'll get a green timeline marker. Double-click it to edit it and choose whether it's a mandatory or optional build-in marker. Everything before that should play at the same speed in FCPX as it does in Motion. The area between the build-in and build-out markers will stretch to fit, and everything after the build-out marker will play as it does in Motion.