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  <section id="creating-units">
<h1>Creating Units<a class="headerlink" href="#creating-units" title="Permalink to this headline">¶</a></h1>
<section id="overview">
<h2>Overview<a class="headerlink" href="#overview" title="Permalink to this headline">¶</a></h2>
<p>There are two distinct concepts you need to keep in mind:</p>
<ul class="simple">
<li><p>Unit <strong>prefab</strong>: a <code class="docutils literal notranslate"><span class="pre">.unit</span></code> resource stored in your project that describes
a Unit hierarchy and all its components and properties.</p></li>
<li><p>Unit <strong>instance</strong>: a concrete instance of that prefab that exists in a
running World.</p></li>
</ul>
<p>You author and edit prefabs in the tools (Level Editor, Unit Editor and
importers). At runtime you instantiate prefabs from Lua and manipulate the
resulting Unit instances.</p>
<p>You do <em>not</em> write <code class="docutils literal notranslate"><span class="pre">.unit</span></code> files from Lua, and you do <em>not</em> author prefabs
directly from gameplay code.</p>
</section>
<section id="from-the-level-editor">
<h2>From the Level Editor<a class="headerlink" href="#from-the-level-editor" title="Permalink to this headline">¶</a></h2>
<p>Prefabs can be created in a number of ways. Arguably the simplest way  to
create new Units is to use the <a class="reference internal" href="../level_editor/level_editor.html#level-editor"><span class="std std-ref">Level Editor</span></a> and then
save what you have built as a prefab.</p>
<ol class="arabic simple">
<li><dl class="simple">
<dt><strong>Open or create a Level</strong></dt><dd><ul class="simple">
<li><p>Open an existing Level from the <a class="reference internal" href="../level_editor/project_browser.html"><span class="doc">Project Browser</span></a>, or</p></li>
<li><p>create a new one with <code class="docutils literal notranslate"><span class="pre">File</span></code> -&gt; <code class="docutils literal notranslate"><span class="pre">New</span> <span class="pre">Level</span></code>.</p></li>
</ul>
</dd>
</dl>
</li>
<li><dl class="simple">
<dt><strong>Place a Unit in the Level</strong></dt><dd><ul class="simple">
<li><p>Place a new unit with <code class="docutils literal notranslate"><span class="pre">Spawn</span></code> -&gt; <code class="docutils literal notranslate"><span class="pre">Primitives</span></code>, or drag an existing
Unit prefab from the Project Browser into
the <a class="reference internal" href="../level_editor/level_viewport.html"><span class="doc">Level Viewport</span></a></p></li>
<li><p>Use the <a class="reference internal" href="../level_editor/inspector.html"><span class="doc">Inspector</span></a> to add or remove components and
to fine‑tune their properties</p></li>
</ul>
</dd>
</dl>
</li>
<li><dl class="simple">
<dt><strong>Save the Unit as prefab</strong></dt><dd><ul class="simple">
<li><p>In the <a class="reference internal" href="../level_editor/level_tree.html"><span class="doc">Level Tree</span></a>, right‑click the Unit you want
to turn into a prefab</p></li>
<li><p>Choose <code class="docutils literal notranslate"><span class="pre">Save</span> <span class="pre">as</span> <span class="pre">Prefab...</span></code></p></li>
<li><p>In the file dialog, pick a target folder and a unique name, then click
<code class="docutils literal notranslate"><span class="pre">Save</span></code></p></li>
</ul>
</dd>
</dl>
</li>
</ol>
<p>The editor will:</p>
<ul class="simple">
<li><p>create a new <code class="docutils literal notranslate"><span class="pre">.unit</span></code> resource at the chosen location</p></li>
<li><p>automatically replace the Unit in the Level with an instance of the newly
created prefab</p></li>
</ul>
<p>From now on:</p>
<ul class="simple">
<li><p>editing the prefab will update all instances that use it unless they
explicitly override properties or children</p></li>
<li><p>editing the instance in the Level will create per‑instance overrides</p></li>
</ul>
</section>
<section id="from-the-project-browser">
<h2>From the Project Browser<a class="headerlink" href="#from-the-project-browser" title="Permalink to this headline">¶</a></h2>
<p>Sometimes you want to start from a blank prefab instead of capturing an
existing Unit from a Level. You can do this directly from the
<a class="reference internal" href="../level_editor/project_browser.html"><span class="doc">Project Browser</span></a>:</p>
<ol class="arabic simple">
<li><p>Right‑click the folder where you want to create the prefab</p></li>
<li><p>Choose <code class="docutils literal notranslate"><span class="pre">New</span> <span class="pre">Unit...</span></code></p></li>
<li><p>Enter a name for the prefab and confirm</p></li>
</ol>
<p>This creates an empty <code class="docutils literal notranslate"><span class="pre">.unit</span></code> resource that you can then edit:</p>
<ul class="simple">
<li><p>by opening it in the Unit Editor, or</p></li>
<li><p>by selecting any instance that uses the prefab in a Level and clicking
<code class="docutils literal notranslate"><span class="pre">Open</span> <span class="pre">Prefab</span></code> in the <a class="reference internal" href="../level_editor/inspector.html"><span class="doc">Inspector</span></a>.</p></li>
</ul>
</section>
<section id="from-imported-resources">
<h2>From imported resources<a class="headerlink" href="#from-imported-resources" title="Permalink to this headline">¶</a></h2>
<p>Some importers generate Units automatically as part of their workflow:</p>
<ul class="simple">
<li><p><a class="reference internal" href="../importing_resources/importing_scenes.html"><span class="doc">Importing Scenes</span></a> generates Units for each
geometry, light and camera in a FBX file.</p></li>
<li><p><a class="reference internal" href="../importing_resources/importing_sprites.html"><span class="doc">Importing Sprites</span></a> generates a Unit prefab,
materials and other resources from a spritesheet.</p></li>
</ul>
<p>These generated Units appear in the Project Browser like any other <code class="docutils literal notranslate"><span class="pre">.unit</span></code>
resource and can be:</p>
<ul class="simple">
<li><p>placed in Levels</p></li>
<li><p>opened and modified in the Unit Editor</p></li>
<li><p>used as base prefabs for derived units</p></li>
</ul>
</section>
<section id="spawning-units">
<h2>Spawning Units<a class="headerlink" href="#spawning-units" title="Permalink to this headline">¶</a></h2>
<p>Lua gameplay code never creates new <code class="docutils literal notranslate"><span class="pre">.unit</span></code> resources. Instead, it creates
instances of existing prefabs inside a World. The act of creating unit
instances at runtime is called <strong>spawning</strong>.</p>
<div class="highlight-lua notranslate"><div class="highlight"><pre><span></span><span class="n">player</span> <span class="o">=</span> <span class="n">World</span><span class="p">.</span><span class="n">spawn_unit</span><span class="p">(</span><span class="n">world</span><span class="p">,</span> <span class="s2">&quot;units/player/player&quot;</span><span class="p">)</span>
</pre></div>
</div>
<p>This:</p>
<ul class="simple">
<li><p>instantiates the unit <code class="docutils literal notranslate"><span class="pre">units/player/player</span></code> into the specified <code class="docutils literal notranslate"><span class="pre">world</span></code></p></li>
<li><p>returns a Unit handle you can store and use from Lua</p></li>
</ul>
<p>See <a class="reference internal" href="../gameplay/unit_interaction.html"><span class="doc">Interacting with Units</span></a> for a detailed walkthrough of unit
handles, Script Component and callbacks.</p>
</section>
</section>


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