V-Ray for Rhino Won't Load (Error: Unable to load VRayForRhino.rhp )

V-Ray for Rhino Won't Load (Error: Unable to load VRayForRhino.rhp )

This article refers to the issue where a user installs V-Ray for Rhino but is unable to get V-Ray to load within Rhino with the following error:

Unable to load VRayForRhino.rhp plug-in: no class derived from CRhinoPlugin in plug-in file

 

This is not a common error because it occurs as the result of a clash with other plugins or .dll (library) files already installed on a Windows machine. It may also clash with a previously installed version of V-Ray.

 

Possible Steps to Resolve

  • Uninstall all other Rhino plugins. Restart Rhino.
  • Check to ensure that the version of V-Ray matches your version of Rhino (eg. they must all be 32bit or all 64bit - but not mixed).
  • Completely uninstall V-Ray and reinstall as administrator (Right-click > Run as administrator..)
  • Completely uninstall V-Ray and Rhino. Reinstall both as administrator.

 

If V-Ray for Rhino is accessing a dll on your system that is out of date or unavailable, try running Dependency Walker to see what libraries it depends on and if any of those are failing. 

 

Additional Information

These dlls are known to conflict.

QtCore4.dll
QtGui4.dll