From: Tristan Croll (
Date: Wed Feb 11 2015 - 15:28:20 CST

Hi Maxim,

Thanks for the hint, but there seems to be only one NVIDIA driver version that will handle this GPU at present - the joys of life on the bleeding edge, I suppose.



Tristan Croll
Faculty of Health
School of Biomedical Sciences
Institute of Health and Biomedical Engineering
Queensland University of Technology
60 Musk Ave
Kelvin Grove QLD 4059 Australia
+61 7 3138 6443
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> On 12 Feb 2015, at 7:17 am, Maxim Belkin <> wrote:
> Tristan, check NVIDIA driver - it can do wonders sometimes.
> Maxim
>> On Feb 11, 2015, at 3:07 PM, Tristan Croll <> wrote:
>> Hi John,
>> Somewhat oddly, this morning (without actually having shut down the machine) I can't seem to reproduce these issues. The interactive renderer now works fine when I close the window, and while the points still resolve as large spheres (each roughly 200 pixels diameter in a 1600 x 1500 OpenGL window) the system is handling the load fine. No idea why because I didn't actually close anything other than VMD itself before leaving it. For the record, this is on an Intel i915 GPU for display / GTX970M for CUDA, driving a somewhat ridiculous native screen resolution of 2880 x 1620 - so it wouldn't surprise me if I was simply running into memory issues. OS is Fedora 21, and up-to-date as of last week. Oh, and it is a final-release copy of VMD 1.9.2.
>> Cheers,
>> Tristan
>> ________________________________________
>> From: John Stone <>
>> Sent: Thursday, 12 February 2015 2:12 AM
>> To: Tristan Croll
>> Cc:
>> Subject: Re: vmd-l: Handful of rendering issues
>> Hi,
>>> On Wed, Feb 11, 2015 at 11:15:19AM +0000, Tristan Croll wrote:
>>> Hi there,
>>> I have a few minor rendering-related issues/suggestions in VMD 1.9.2:
>>> - If I have an isosurface visualised in the default point representation
>>> and switch to GLSL rendermode, every point becomes a VERY large sphere and
>>> the system slows to a crawl.
>> What kind of GPU are you using? The point rendering in this case should be
>> relatively harmless on a normal GPU. I wonder if there's a bug in the video
>> driver affecting you there.
>>> - When a wireframe is rendered in Tachyon the lines are of course replaced
>>> by thin cylinders. This works out nicely in the CPU-only Tachyon
>>> (particularly if I use a transparent material, yielding a nicely
>>> unobtrusive mesh), but the cylinder diameter is much larger in
>>> Tachyon-OptiX. Is it possible to shrink this, or is this one of the
>>> trade-offs that allows the renderer to be so blazingly fast?
>> There are still a lot of minor differences between the full Tachyon and the
>> "light weight" GPU-accelerated version that I've implemented in VMD.
>> The behavior of line rendering on the GPU version leaves something to be
>> desired, I hope to improve that in the next release, and I will also
>> implement some of the missing features such as 3-D texturing and
>> user-defined clipping planes, which are not implemented in the GPU ray tracer
>> up to this point.
>>> - When using the interactive renderer, closing the rendering window with
>>> the mouse rather than pressing Esc or q crashes VMD.
>> This works fine for me using the final version of VMD 1.9.2.
>> If you're running a pre-release test version of VMD, you should upgrade
>> to the final release. If you're running the final version of VMD 1.9.2,
>> then I'm going to need to know a lot of other details about your machine,
>> such as what OS version you're running, what window manager, and so on.
>> The only way I've found to create a scenario similar to what you describe
>> is to use "xkill" on VMD, which terminates the program abruptly (but that's
>> the whole point of xkill, so I don't see that as wrong behavior).
>>> - I think it would be awesome if the interactive renderer had an option to
>>> render the scene at some multiple of the screen resolution, for when
>>> poster-quality images are needed.
>> This is something Axel had suggested early on, but it turns out to be
>> somewhat trickier than I had originally anticipated, due to the greatly
>> increased possibility for GPU kernel timeouts. I decided to leave this
>> feature for the next release so I can work on the code a bit more and
>> try to decrease the likelihood of GPU kernel timeouts on low-end GPUs.
>> That said, it's on the TODO list already with many other improvements.
>> Cheers,
>> John Stone
>>> Cheers,
>>> Tristan
>> --
>> 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