title: Artifacts when capturing bitmap from Viewport3D?
body: <p>I'm trying capture an image from a Viewport3D element in a WPF app. It works fine when the 3D models in the viewport are relatively close to the camera, but if I zoom out then artifacts start to show up. It seems like some kind of perspective thing, but I'm not sure why. The model seems to flatten out the more I zoom.</p>
  
  <p>I'm using <a href="https://github.com/helix-toolkit/helix-toolkit" rel="nofollow noreferrer">Helix Toolkit</a> as the framework wrapping the 3D stuff, so my first try was to capture using <code>Viewport3DHelper.SaveBitmap()</code>, after that I tried using a more generic <code>UIElement</code> approach using a <code>RenderTargetBitmap</code> and writing it to disk via a <code>PngBitmapEncoder</code>. These yielded the same results.</p>
  
  <p>My camera in question is a <code>PerspectiveCamera</code>, where I set the position, look direction, up direction, and the far plane distance (which I hadn't changed until trying to solve this).</p>
  
  <p>Any thoughts or suggestions would be much appreciated.</p>
  
  <p><a href="https://i.stack.imgur.com/7png5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7png5.png" alt="Zoomed in"></a>
  <a href="https://i.stack.imgur.com/OyytX.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/OyytX.png" alt="Zoomed out"></a></p>
  
  <p>EDIT: Note  this that issue does not appear when using an <code>OrthographicCamera</code>.</p>