This page provides some information on how to get V-Ray up and running.
Installing V-Ray
The V-Ray installer for Revit is straightforward and easy to follow. It can be downloaded from the V-Ray | Downloads section of the Chaos Group website (please make sure you use your login credentials to ensure access to the download links). Before installing V-Ray, it is recommended to check that your computer meets the System Requirements for running Revit with V-Ray. If you would like a step-by-step guide, please check out the Installation of V-Ray for Revit page.
Licensing V-Ray
Once V-Ray is installed you will want to make sure that your V-Ray license is properly configured. The Setting Up Your V-Ray License page includes everything you need to get V-Ray licensed and running properly.
Running V-Ray for the first time
By default, when Revit is launched, your V-Ray for Revit license will not be automatically engaged and you will see the V-Ray toolbar grayed out.
To pull your license and start using V-Ray, simply press the Enable V-Ray button. When Revit is closed, your V-Ray license will be released automatically.
If you prefer your V-Ray license to be engaged automatically every time when Revit is loaded, use the Obtain License on start-up option.