user589: I'm producing a video with several graphics animations, and some of them need to be done in Motion. What's the best way to store a Motion animation that will only be used in one place in one FCP project?
Motion appears to want me to save it as a FCP template, but then it'll be in that template list for all time. I want to keep it with the project, ideally in an Event. It's media, just like my video and audio.
Is there any good way to handle this?

user5569: FCPX has currently no way to link Motion Projects to FCPX Projects. To place Motion Projects in another directory than the default one, you have to create symbolic links using Terminal (see below). Motion Projects can only be used in FCPX as Templates.
From Apple's PDF "Managing Media with Final Cut Pro X Libraries":

Motion templates are not managed as assets within the library but are instead stored in ~/Movies/Motion Templates/. If a project is dependent on custom titles or other Motion templates, these must be handed off separately.

I. Managing Motion Templates Manually
FCPX searches for Motion Templates in ~/Movies/Motion Templates/Type of effect/Category/Name of effect/.

~/ means your home directory
Type of effect is one of: Compositions, Effects, Generators, Titles, Transitions.
Category, Name of effect: the name and the category under which the effect will appear in FCPX. 

Within Finder you can :

Change the names of categories and effects
Create new categories and rearrange the effects inside them
update: New templates are detected without restarting, removed templates will show as offline until restarted

You can for example put all project-specific effects in a category named after that project. When you archive your project, you move the category's folder along and it will disappear in FCPX.
Update:
II. Templates Outside Templates Folder (Requires Terminal)

Find your Template (see above) and move it using Finder
In the Terminal create a symbolic link to your Templates new location (while aliases from the Finder are not recognized, symbolic links created in the Terminal are)
ln -s /Volumes/ExternalHDD/Untitled.fcpbundle/MyTitle.moti \
      ~/Movies/Motion\ Templates.localized/Titles.localized/MyCategory/

Change the above folder names to reflect yours.
In this example the Template is inside a Library on an external drive! See the next section on how to get it there.
To use this drive on another Mac, repeat the Terminal command there.

III. Templates Inside Library
To make sure a Template stays with the project it belongs to, you can place it inside the project's .fcpbundle:

In FCPX control-click on your library and choose Reveal in Finder

In Finder control-click on your library and choose Show Package Contents

Find your Template (see I.) and place it here. Then create the symbolic link (see II.)

Credits for Terminal inspiration go to MacBreak Studio.

589: <p>I'm producing a video with several graphics animations, and some of them need to be done in Motion. What's the best way to store a Motion animation that will only be used in one place in one FCP project?</p>

<p>Motion appears to want me to save it as a FCP template, but then it'll be in that template list for all time. I want to keep it with the project, ideally in an Event. It's media, just like my video and audio.</p>

<p>Is there any good way to handle this?</p>
 5569: <p>FCPX has currently no way to link Motion Projects to FCPX Projects. To place Motion Projects in another directory than the default one, you have to create symbolic links using Terminal (see below). Motion Projects can <em>only</em> be used in FCPX as <em>Templates</em>.</p>

<p>From Apple's <a href="https://www.apple.com/final-cut-pro/docs/Media_Management.pdf" rel="nofollow noreferrer">PDF</a> <em>"Managing Media with Final Cut Pro X Libraries"</em>:</p>

<blockquote>
  <p>Motion templates are not managed as assets within the library but are instead stored in ~/Movies/Motion Templates/. If a project is dependent on custom titles or other Motion templates, these must be handed off separately.</p>
</blockquote>

<h2>I. Managing Motion Templates Manually</h2>

<p>FCPX searches for Motion Templates in <code>~/Movies/Motion Templates/</code><em><code>Type of effect</code></em><code>/</code><em><code>Category</code></em><code>/</code><em><code>Name of effect</code></em><code>/</code>.</p>

<ul>
<li><strong><code>~/</code></strong> means your home directory</li>
<li><strong><code>Type of effect</code></strong> is one of: Compositions, Effects, Generators, Titles, Transitions.</li>
<li><strong><code>Category</code></strong>, <strong><code>Name of effect</code></strong>: the name and the category under which the effect will appear in FCPX. </li>
</ul>

<p>Within Finder you can :</p>

<ul>
<li>Change the names of categories and effects</li>
<li>Create new categories and rearrange the effects inside them</li>
<li>update: New templates are detected without restarting, removed templates will show as offline until restarted</li>
</ul>

<p>You can for example put all project-specific effects in a category named after that project. When you archive your project, you move the category's folder along and it will disappear in FCPX.</p>

<p><strong>Update:</strong></p>

<h2>II. Templates Outside Templates Folder (Requires Terminal)</h2>

<ol start="3">
<li>Find your Template (see above) and move it using Finder</li>
<li><p>In the Terminal create a symbolic link to your Templates new location (while aliases from the Finder are not recognized, symbolic links created in the Terminal <em>are</em>)</p>

<pre><code>ln -s /Volumes/ExternalHDD/Untitled.fcpbundle/MyTitle.moti \
      ~/Movies/Motion\ Templates.localized/Titles.localized/MyCategory/
</code></pre>

<p>Change the above folder names to reflect yours.</p>

<p>In this example the Template is inside a Library on an external drive! See the next section on how to get it there.</p></li>
<li><p>To use this drive on another Mac, repeat the Terminal command there.</p></li>
</ol>

<h2>III. Templates Inside Library</h2>

<p>To make sure a Template stays with the project it belongs to, you can place it inside the project's .fcpbundle:</p>

<ol>
<li><p>In FCPX control-click on your library and choose Reveal in Finder</p>

<p><img src="https://i.stack.imgur.com/5wTt7.png" alt="Reveal in Finder"></p></li>
<li><p>In Finder control-click on your library and choose Show Package Contents</p>

<p><img src="https://i.stack.imgur.com/oNuvo.png" alt="Show Package Contents"></p></li>
<li><p>Find your Template (see I.) and place it here. Then create the symbolic link (see II.)</p></li>
</ol>

<p>Credits for Terminal inspiration go to <a href="http://youtu.be/hCXQmYgBxeI" rel="nofollow noreferrer">MacBreak Studio</a>.</p>
