title: Forge Viewer: changing fragment material
body: <p>Is there a way to change the material of an existing fragment? I see there is a <a href="https://forge.autodesk.com/en/docs/viewer/v7/reference/Extensions/ModelBuilder/#changefragmentmaterial-fragment-material" rel="nofollow noreferrer">changing fragment material</a> function in the documentation, but this seems to be for adding custom models, rather than manipulating existing fragments in the viewer.</p>
  <p>I specifically wish to change the material so I can manipulate the linewidth of the fragment. I've tried manipulating the <code>fragments</code> of <code>viewer.model.getFragmentList()</code>, specifically <code>Viewer.model.getFragmentList().getMaterial(i)</code> and its properties (such as <code>linewidth</code>) to no avail, even after updating via <code>viewer.impl.invalidate</code></p>