Caustic Visualizer for Autodesk 3ds Max enables 3D artists to accelerate their workflows by greatly reducing time spent on “iterative” scene refinement. Unlike other accelerated viewports, Visualizer's beautifully raytraced ActiveShade environment allows scenes to be viewed and modified in real-time using 3ds Max's standard modeling, animation and lighting toolsets - including mental ray.
To take part in the beta, you’ll need to be running 3ds Max 2012+ on Windows 7 or 8. Although by this time the website hasn’t been updated, the developer has confirmed on Twitter the program is now open.
For more info (including link to beta program) visit: caustic