From: John Stone (
Date: Thu Oct 30 2014 - 11:33:12 CDT

  Since VMD 1.9.2 beta 1 was released, I have been working
hard on making the first version of a new interactive GPU ray
tracing feature available before VMD 1.9.2 ships. I have had
a small group of people testing the code up until now, but I
think it's time to get feedback from a broader range of users,
particularly since several hundred people have already been
downloading and testing the previous VMD beta version that
includes the batch-only version of the GPU ray tracer.

The new VMD build _REQUIRES_ the latest NVIDIA driver versions.
You MUST be running NVIDIA driver version 344.xx or later otherwise
you will not be able to use new GPU ray tracer.
Best results will be obtained on GPUs that contain several gigabytes
of GPU memory. GPUs with 4GB of memory are in the sweet spot where
you can render even fairly large scenes without running out of memory.

The reward for going through the trouble to update to the latest
driver version is that this new version of VMD can do real-time
interactive ray tracing for large molecular scenes, at rates of
20 to 60 frames per second, even when sophisticated rendering
effects such as ambient occlusion light or depth of field are
enabled, by virtue of the use of a progressive rendering approach
that refines the image when the view orientation is not changing.

The new interactive GPU ray tracer is currently listed in the VMD
File|Render menu as "TachyonL-OptiX (live real-time GPU display)".

The interactive ray tracer will open a new graphics display window,
which uses similar control keys to the main VMD graphics display,
and it also supports the use of the SpaceNavigator input devices.

I have posted a 64-bit Linux VMD test build for RHEL 5.x systems,
and I'm writing initial documentation for it here:

The new VMD test version also supports depth-of-field rendering in
the standard CPU versions Tachyon, and POV-Ray.

I would appreciate feedback users have when they begin testing
the new features. I will be updating the documentation as
questions, problems, and solutions arise.

  John Stone

NIH Center for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801           Phone: 217-244-3349