<p dir="auto">when i set a object(which instanced Line2).scale.x &lt; 0, Line2 disappeared? is it normal?</p>
<p dir="auto"><em><strong>Live example</strong></em></p>
<ul dir="auto">
<li><a href="https://codesandbox.io/s/lucid-browser-36v9e" rel="nofollow">jsfiddle-latest-release</a></li>
</ul>
<p dir="auto">As the title say: a <a href="https://github.com/mrdoob/three.js/blob/r98/examples/js/lines/Line2.js">Line2</a> disappears completely when the scale is set to negative on a single axis <code class="notranslate">line2.scale.set(-1, 1, 1)</code>. The line is obviously still there but it's not rendered.</p>
<p dir="auto">Weirdly, if the scale is set to negative on more than one axis <code class="notranslate">line2.scale.set(-1, -1, 1)</code>, the line appears again.</p>
<p dir="auto">Here's a jsfiddle that demonstrates the issue: <a href="https://jsfiddle.net/jacopocolo/5fsotdpw/16/" rel="nofollow">https://jsfiddle.net/jacopocolo/5fsotdpw/16/</a><br>
Toggling <code class="notranslate">wireframeToggle</code> on line 7 to true shows two Line2 in wireframe but if <code class="notranslate">wireframeToggle</code> is set to false, only one is visible.</p>
<h5 dir="auto">Three.js version</h5>
<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> Dev</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> r117</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> ...</li>
</ul>
<h5 dir="auto">Browser</h5>
<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> All of them</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> Chrome</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> Firefox</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> Internet Explorer</li>
</ul>
<h5 dir="auto">OS</h5>
<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> All of them</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> Windows</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> macOS (only tested here)</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> Linux</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> Android</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> iOS</li>
</ul>