nCV:</h3>
<div class="paragraph">
<p>By default pip will fetch and build OpenCV (on windows, it will fetch a precompiled version). You can select a specific version by setting the environment variable <code>OpenCV_DIR</code></p>
</div>
<div class="sect3">
<h4 id="_touristic_note_4_ways_to_set_an_env_var_with_windows">Touristic note: 4 ways to set an env var with Windows</h4>
<div class="paragraph">
<p>There are at least 4 incompatible ways to set an env var in Windows:</p>
</div>
<div class="ulist">
<ul>
<l