From: Pawel Wielgus (
Date: Mon Mar 12 2007 - 03:00:45 CDT

Dear John,

after exporting the system variable, I can see sth like this:

Info) File loading in progress, please wait.
Info) Using plugin cube for structure file test.cube
cubeplugin) trying to read cube data set 0
Info) Analyzing Volume...
Info) Grid size: 80x80x80 (7 MB)
Info) Total voxels: 512000
Info) Min: 0.000000 Max: 0.706192 Range: 0.706192
Info) Computing volume gradient map for smooth shading
Info) Added volume data, name=test.cube : Gaussian Cube: kom density=scf
Info) Using plugin cube for coordinates from file test.cube
Info) Determining bond structure from distance search ...
Info) Finished with coordinate file test.cube.

Looks not bad. But that's all. I still can't see anything on my screen
when the VolumeSlice representation is chosen :(


John Stone wrote:
> Pawel,
> Ah, I see the issue. Well, you have a choice of either force-enabling
> full rendering functionality (and risking crashes due to a number of
> known ATI driver bugs that are to my knowledge still not fixed based
> on recent reports from others), or using a different machine or a different
> video card. If you wish to take your chances with the ATI video driver
> and tell VMD to enable all rendering features, you can do this by
> setting the environment variable VMDDISABLEATILINUXWORKAROUND, like this:
> After setting that environment variable, you should be able to start
> VMD again, but without the functionality limitations imposed by default
> when an ATI Linux driver is detected. Do not be surprised if you manage
> to crash VMD, the X server, or even lockup your machine, as I've seen all
> of these situations occur with both the open source and ATI provided
> drivers for Linux. Oddly, the same hardware works fine with the ATI
> provided Windows driver, so I think this is mainly an issue with their
> Linux driver series.
> If you're able to use VMD reliably with full features with your ATI
> Linux driver I would be very interested to hear about it, as many other
> ATI users have encountered stability problems when using the advanced OpenGL
> rendering features. Any tips that help others with their ATI drivers
> are appreciated.
> If you have stability problems when full functionality is enabled I would
> report this to ATI on their support forums. If you don't get a response
> from them, then it may be time to consider getting a different video card
> if working with volumetric data is important to you.
> John Stone
> On Fri, Mar 09, 2007 at 04:54:26PM +0100, Pawel Wielgus wrote:
>>Thanks for your reply.
>>When my VMD starts, one can read:
>>Info) ATI Linux driver detected, limiting features to avoid driver bugs.
>>Info) OpenGL renderer: MOBILITY RADEON X300 Generic
>>Info) GLSL rendering mode is NOT available.
>>Info) Textures: 2-D (2048x2048), 3-D (2048x2048x2048), Multitexture (8)
>>I really don't know what 'limiting features' mean. What I know for sure
>>is that I really had lots of troubles when compiling ATI fglrx drivers.
>>And I did it finally only against 2.6.10 kernel. But that's a long story...
>>What do you think? Any special features in fglrx configuration needed ?
>>John Stone wrote:
>>> Yes, the VolumeSlice representation has been available for some time
>>>and should work fine so long as you have a video card that supports
>>>3-D (volumetric) texturing. You can check this by reading the VMD OpenGL
>>>related startup messages. You should see a texturing info line like
>>>the one I've pasted below:
>>> Info) OpenGL renderer: ZFB, VIS
>>> Info) Features: STENCIL MSAA(16) MDE MTX GAS
>>> Info) Textures: 2-D (4096x4096), 3-D (512x512x512), Multitexture (4)
>>>The important part of that status line is: "3-D (512x512x512)"
>>>What video chipset are you using? Have you checked to make sure
>>>that you're using the latest video driver available for your hardware?
>>> John Stone
>>>On Fri, Mar 09, 2007 at 04:27:17PM +0100, Pawel Wielgus wrote:
>>>>Dear VMD Users,
>>>>may I ask you a question concerning the visualization of volumetric data?
>>>>I have a simple example of density for CH4 (just for graphical testing)
>>>>in a Gaussian03 cube format. The volumetric data is read properly, and
>>>>using 'Drawing method = Isosurface' I can easily get the density.
>>>>But as only I switch to 'Drawing method = VolumeSlice' everything
>>>>disapears. As far as I know the volume slices (along cartesian axis) are
>>>>possible with VMD-1.8.5.
>>>>What wrong am I doing ? Should I switch any options on ? Could you give
>>>>me any hint?
>>>>Pawel Wielgus