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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>If I want to use the multi-pass framework to do volume rendering in an existing OpenGL context, with an existing camera/lights etc how is the best way to proceed?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have created a function called Render(), which basically calls:<o:p></o:p></p><p class=MsoNormal>void VtkRender()<o:p></o:p></p><p class=MsoNormal>{<o:p></o:p></p><p class=MsoNormal>opaquePass->Render(state);<o:p></o:p></p><p class=MsoNormal>peelingPass->Render(state);<o:p></o:p></p><p class=MsoNormal>volumetricPass->Render(state);<o:p></o:p></p><p class=MsoNormal>overlayPass->Render(state);<o:p></o:p></p><p class=MsoNormal>}<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I don’t make these passes a delegate sequence of a vtkCameraPass. In addition I don’t perform a light pass using vtkLightsPass. Instead the camera pass and light passes are done before calling VtkRender() using non-VTK code.<o:p></o:p></p><p class=MsoNormal>For opaque and translucent props it works quite well. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'>However, the volumetric pass does not work yet. I have stepped through the code in Debug mode and checked all calls done during the volume rendering (using a <span style='font-size:9.5pt;font-family:Consolas'>vtkVolumeRayCastMapper</span>).<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'>It obviously is trying to get certain values (e.g. transformations) from the vtkCamera of the vtkRenderer. This vtkCamera is otherwise not used and not setup or synched with the existing non-VTK camera.<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'>How can I set up the vtkCamera so that this will work? Could there be another reason why it is not working for volume rendering, but working correctly for opaque/depth peeling render passes?<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'>If I get this to work I will add a self contained example to the Wiki Examples.<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'>Thanks for any hints<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'>Bryn<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>