[abenedik]

After checking the sample code of the mjtrainor it turned out that the problem was caused because the object that rendered the WireframeVisual3D in DXEngine (WpfWireframeVisual3DNode) can change the rendering effect of the object it is rendering.

In case of mjtrainor the object was rendered twice - once within WireframeVisual3D and once on its own. When the WireframeVisual3D.WireframeType is set to Wireframe, then this also changes the rendering type of the object to wireframe rendering. This renders the object twice as wireframe object.

The recommended way to solve this is to render the object only once and set the WireframeVisual3D.WireframeType to one of the following:

• WireframeWithOriginalSolidModel
  
• Wireframe
  
• OriginalSolidModel
  
• None
  

Then the WpfWireframeVisual3DNode will correctly render the wireframe and the solid object.

If you want to still render the meshModel separately then please create the new instances of GeometryModel3D (and Model3DGroup) objects - you can preserve the MeshGeometry3D.