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+<head>
+<title>Flightgear External Model Mini-HowTo</title>
+</head>
+
+<body bgcolor="white">
+<h1>FlightGear External Model Mini-HowTo</h1>
+
+<img src="model.jpg" />
+
+<p>FlightGear now supports external views with user-defined 3D models.
+Eventually, FlightGear will probably support a single definition file
+that specifies a package containing a flight model, engine model,
+panel, external 3D model, and sounds; for now, however, users must
+specify each of these separately.</p>
+
+<p>FlightGear uses the open-source <a
+href="http://plib.sourceforge.net/">PLIB</a> library, which (as of
+version 1.3.1) includes support for several 3D file formats:</p>
+
+<ul>
+<li>VRML</li>
+<li>3DS</li>
+<li>AC3D</li>
+<li>SSG (its native format)</li>
+<li>ASE</li>
+<li>DXF</li>
+<li>TRI</li>
+<li>OBJ</li>
+<li>MD2</li>
+<li>MDL (<cite>Microsoft Flight Simulator</cite> format)</li>
+</ul>
+
+<p>(Note that some of these have restrictions; see the PLIB
+documentation for details.) As new formats are added to PLIB,
+FlightGear will automatically be able to support them.</p>
+
+<p>First, you need to find a 3D model for the aircraft you want to see
+during an external view. Your best bet is probably to download an
+MSFS MDL file from one of the many flight-simulator Web sites, such as
+<a href="http://www.flightsim.com/">www.flightsim.com</a>. You then
+need to install the main model file (with the appropriate extension)
+somewhere under <code>$FG_ROOT</code>, and install any associated
+textures in <code>$FG_ROOT/Models/Textures</code>.</p>
+
+<blockquote>
+<p><strong>NOTE: if your model appears untextured and you are
+using a case-sensitive filesystem, you may need to fiddle with the
+case of the texture file names.</strong></p>
+</blockquote>
+
+<p>Next, you need to set the property <code>/sim/model/path</code> to
+the model file's name, relative to $FG_ROOT.</p>
+
+<p>It is possible that the model may not be aligned correctly, and
+will appear to fly too high, too low, sideways, vertically, etc. If
+so, you can use the additional properties described at the end of this
+mini-howto to adjust to model so that it appears to fly
+realistically.</p>
+
+
+<div>
+<h2>Example</h2>
+
+<p>You have downloaded a zip package containing a 3D Cessna model for
+Microsoft Flight Simulator, and you want to use that model in
+FlightGear. First, you unzip the package, where you find a series of
+files, including one with the extension "<code>mdl</code>" and several
+with extensions ending in "<code>af</code>"; you can safely ignore any
+other files for the installation, but you should, of course, read any
+files describing your usage rights.</p>
+
+<p>Change to the location of <code>$FG_ROOT</code>
+(<code>/usr/local/FlightGear</code> on my system) and copy all of the
+<code>*af</code> texture files to <code>Models/Textures/</code>. In
+Unix, assuming you unzipped in /tmp/cessna</p>
+
+<pre>
+cp /tmp/cessna/*af Models/Textures
+</pre>
+
+<p>Next, copy to <code>*.mdl</code> file to any location under
+$FG_ROOT; it's probably a good idea to put it inside
+<code>Models/</code>. In Unix</p>
+
+<pre>
+cp /tmp/cessna/*.mdl Models
+</pre>
+
+<p>To use the model in FlightGear, use the <var>--prop</var> option
+with the <code>/sim/model/path</code> property:</p>
+
+<pre>
+fgfs --prop:/sim/model/path=Models/C172SKH.mdl
+</pre>
+
+<p>Press the 'v' key to switch to external view, and see how it
+looks.</p>
+
+<p>If the model does seem to have the correct position or orientation,
+you can adjust it using the properties described below. When
+everything is correct, you can add the properties to your .fgfsrc file
+so that you do not have to type them every time.</p>
+
+<!-- end of "Example" -->
+</div>
+
+
+<div>
+<h2>Properties</h2>
+
+<p>These properties allow you to specify the path of the 3D model for
+external views and to adjust the model's position and orientation so
+that it seems to fly in the correct position. For example, if the
+model is pointing backwards, you can specify</p>
+
+<pre>
+--prop:/sim/model/h-rotation=180
+</pre>
+
+<p>to turn it around the right way. If the model seems to float a
+half meter above the ground, you can specify</p>
+
+<pre>
+--prop:/sim/model/z-offset=0.5
+</pre>
+
+<p>to lower it a bit.</p>
+
+<table border="1">
+
+<thead>
+<tr>
+<th>Property</th>
+<th>Default</th>
+<th>Description</th>
+</tr>
+</thead>
+
+<tbody>
+<tr>
+<td><code>/sim/model/path</code></td>
+<td align="center"><code>Models/Geometry/glider.ac</code></td>
+<td>The pathname of a file containing a 3D model, relative to
+<code>$FG_ROOT</code>.</td>
+</tr>
+<tr>
+<td><code>/sim/model/x-offset</code></td>
+<td align="center"><code>0.0</code></td>
+<td>The backward/forward offset in meters. Positive is backwards,
+negative is forwards.</td>
+</tr>
+<tr>
+<td><code>/sim/model/y-offset</code></td>
+<td align="center"><code>0.0</code></td>
+<td>The left/right offset in meters. Positive is right, negative is
+left.</td>
+</tr>
+<tr>
+<td><code>/sim/model/z-offset</code></td>
+<td align="center"><code>0.0</code></td>
+<td>The up/down offset in meters. Positive is down, negative is
+up.</td>
+</tr>
+<tr>
+<td><code>/sim/model/h-rotation</code></td>
+<td align="center"><code>0.0</code></td>
+<td>The heading rotation in degrees. Positive is counter-clockwise,
+negative is clockwise.</td>
+</tr>
+<tr>
+<td><code>/sim/model/p-rotation</code></td>
+<td align="center"><code>0.0</code></td>
+<td>The bank rotation in degrees. Positive is left bank, negative is
+right bank.</td>
+</tr>
+<tr>
+<td><code>/sim/model/r-rotation</code>
+<td align="center"><code>0.0</code></td>
+<td>The pitch rotation in degrees. Positive is nose up, negative is
+nose down.</td>
+</tr>
+</tbody>
+
+</table>
+
+<!-- end of "Properties" -->
+</div>
+
+<hr />
+
+<address>David Megginson,
+<a href="mailto:david@megginson.com">david@megginson.com</a>,
+2000-11-08</address>
+
+</body>
+</html>
projects / flightgear.git / commitdiff
