The missing piece between Final Cut Pro X and Motion 5: Xsend Motion from Automatic Duck.
Xsend Motion converts your FCPX timeline into a Motion project in just seconds, translating Transforms like Position and Scale, opacity and blending modes, titles and many third party effects as well.
A new Motion project is created pointing to the same media files used by Final Cut Pro, no new media is created. You can easily adjust your footage in Motion, everything is live and not baked-in.
You can send an entire project from FCPX to Motion, or you can export the contents of a compound clip to XML and translate that into Motion. Your Motion work can be exported back to FCPX as a QuickTime movie or published as a Generator, Xsend Motion fits into your workflow. Any time you have a clip or set of clips in FCPX that want to use in Motion, Xsend Motion is the tool you need to send those projects across.
Xsend Motion integrates with the Final Cut Pro X Share menu as well as with XML exports from FCPX 10.2.1 and later.