<div dir="ltr">I'm not sure if this is your issue, but you might try using a triangle filter on your data. For OpenGL we do not guarantee correct rendering of concave polygons. The triangle filter will convert a concave polygon into convex triangles which should render correctly.</div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Oct 18, 2016 at 2:20 AM, Stefan Melber <span dir="ltr"><<a href="mailto:Stefan.Melber@dlr.de" target="_blank">Stefan.Melber@dlr.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
  
    
  
  <div bgcolor="#ffffff" text="#000000">
    Hi,<br>
    <br>
    i found a rendering problem with cuts through polyhedral cells
    depending on which rendering backend is used. For example in PV
    5.1.2 compiled with<br>
    <br>
    VTK_RENDERING_BACKEND = OpenGL<br>
    <br>
    a cut looks like error.opengl.v5_1_2.png - there is a wrong shading
    and some facets coming from the wrong starting point.<br>
    <br>
    Switching to OpenGL2 everything is fine (error.opengl2.v5_1_2.png).
    This problem is the same with ParaView 5.2.0RC1 and OpenGL or
    OpenGL2 - however there seems to be an additional (smaller) problem
    using OpenGL2: there are some lines drawn outside of the shell - see
    error.opengl2.v5_2_0rc1.png (cutted on a different position).<br>
    <br>
    The example cell is for testing is attached as "error.vtk" - cut
    e.g. in x-direction on different positions to get the described
    effects.<br>
    <br>
    Best regards,<br>
    <br>
           Stefan<br>
    <br>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature">Ken Martin PhD<div>Chairman & CFO<br>Kitware Inc.<br>28 Corporate Drive<br>Clifton Park NY 12065<br>518 371 3971<div><br></div><div><span style="font-size:10pt;font-family:Tahoma,sans-serif">This communication,
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