VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Fri Feb 13 2015 - 09:42:02 CST

Norman,
  Okay, so "Trbvh" is breaking on your machine, at least in two different
cases, but "MedianBvh" works. I assume your crash when rendering the
single sphere has also gone away. I'm currently running NVIDIA driver
version 346.35 and I was not able to reproduce either your crashes
locally, but I was testing on different GPU types than you did.
I know it's a hassle, but if you have time to upgrade your driver to
a newer version like 346.35, I'd love to know if that makes any difference
for the problems you have reported or not. If not, then we have found
something amiss, most likely with the "Trbvh" builder, and we'll want to
do further tests on this. I am beginning to test the prerelease version of
OptiX 3.7, and it has a newer "Trbvh" builder that reportedly includes some
more bug fixes, so I would like to have you try a new VMD build that includes
that if possible in the next couple weeks.

The issue with the odd appearance of the ruler is due to the emulation of
lines with cylinders, and is expected until I have time to improve it
further. The line emulation in the OptiX code isn't as good as the one
in Tachyon yet, but I will be working on that for the next release.

Cheers,
  John

On Fri, Feb 13, 2015 at 04:25:36PM +0100, Norman Geist wrote:
> John,
>
> I've tested doing:
>
> 1. open VMD
> 2. disable axis
> 3. enable ruler
> 4. set env(VMDOPTIXBUILDER) "MedianBvh"
> 5. render using TachyonOptix
>
> This worked, although the ruler looked weirdly bended.
> In the same VMD session a switching to "Trbvh" again, brought
> the error back.
>
> Hope that helps
>
> Norman Geist
>
> > -----Original Message-----
> > From: John Stone [mailto:johns_at_ks.uiuc.edu]
> > Sent: Friday, February 13, 2015 3:55 PM
> > To: Norman Geist
> > Cc: VMD Mailing List
> > Subject: Re: vmd-l: Handful of rendering issues
> >
> > Norman,
> > Please try this experiment for me:
> > Set the environment variable VMDOPTIXBUILDER to "MedianBvh"
> > and try rendering the same scenes you have been rendering that
> > caused trouble. I'm suspicious that you have found some kind
> > of bug in the "Trbvh" builder in OptiX 3.6.x, because there were
> > a string of buglets that got fixed in "Trbvh" and I wonder if
> > there were still a few more hanging out there. Switching to
> > "MedianBvh" changes nothing that VMD does, but it changes which
> > acceleration structure builder OptiX uses internally, and the
> > "MedianBvh", while not as fast as "Trbvh" has been reliable for
> > me in VMD for a long time now, and has performed correctly in all
> > of the cases where "Trbvh" has broken.
> >
> > Make sure you get the capitalization of the builder string correct
> > or OptiX will ignore it.
> >
> > Cheers,
> > John Stone
> > vmd_at_ks.uiuc.edu
> >
> >
> > On Fri, Feb 13, 2015 at 08:42:15AM +0100, Norman Geist wrote:
> > > John,
> > >
> > > the GPU has 2GB of VRAM. Nothing else, except KDE4 is running.
> > > Before starting VMD, nvidia-smi shows 158MB out of 2047MB used.
> > > After starting VMD, nvidia-smi shows 282MB out of 2047MB used.
> > >
> > > So rendering only the ruler then breaks the renderer. My 1st guess
> > was that
> > > the "empty" ruler molecule
> > > having only drawn objects, doesn't have the expected molecule memory
> > > structure set up which TachyonOptix tries to
> > > transfer to the GPU. Therefore I tried the following, which will lead
> > to the
> > > same error:
> > >
> > > 1. open fresh vmd
> > > 2. disable axis
> > > 3. mol new
> > > 4. graphics 0 sphere {1 1 1}
> > > 5. render using tachyonoptix
> > >
> > > Let me know if I can help to dig it down further.
> > >
> > > Norman Geist.
> > >
> > > > -----Original Message-----
> > > > From: John Stone [mailto:johns_at_ks.uiuc.edu]
> > > > Sent: Thursday, February 12, 2015 4:16 PM
> > > > To: Norman Geist
> > > > Cc: VMD Mailing List
> > > > Subject: Re: vmd-l: Handful of rendering issues
> > > >
> > > > Norman,
> > > > How much video memory does your GPU have?
> > > > What else are you running on the machine at the time that this
> > > > error occurs? (for example, is Google Chrome running? Other
> > > > instances of VMD? Anything else that uses the GPU at all?)
> > > >
> > > > Cheers,
> > > > John
> > > >
> > > > On Thu, Feb 12, 2015 at 09:44:34AM +0100, Norman Geist wrote:
> > > > > Hey John,
> > > > >
> > > > > the exact error message is:
> > > > >
> > > > > ERROR) OptiXRenderer) ERROR: Unknown error (Details: Function
> > > > "RTresult
> > > > > _rtContextLaunch2D(RTcontext, unsigned int, RTsize, RTsize)"
> > caught
> > > > > exception: (bvhtools error)An unexpected memory allocation error
> > > > occurred in
> > > > > TrivialThrustAllocator, [21823538], [15270173])
> > (OptiXRenderer.C:1188
> > > > >
> > > > > GPU is a Geforce GTX660 (propritary NVidia driver version:
> > 343.22)
> > > > >
> > > > > This error occurs for me doing the following steps:
> > > > >
> > > > > 1. open a fresh vmd
> > > > > 2. disable axis
> > > > > 3. enable ruler in scale mode
> > > > > 4. render using TachyonOptix (interactive or not)
> > > > >
> > > > > Norman Geist.
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: John Stone [mailto:johns_at_ks.uiuc.edu]
> > > > > > Sent: Wednesday, February 11, 2015 5:21 PM
> > > > > > To: Norman Geist
> > > > > > Cc: 'Tristan Croll'; VMD Mailing List
> > > > > > Subject: Re: vmd-l: Handful of rendering issues
> > > > > >
> > > > > > Norman,
> > > > > >
> > > > > > On Wed, Feb 11, 2015 at 04:32:35PM +0100, Norman Geist wrote:
> > > > > > > 1. Using the "ruler" in "scale" mode, when nothing
> > else
> > > > > > (including
> > > > > > > axis) is visible, TachyonOptix will crash.
> > > > > >
> > > > > > I don't get a crash when I do this on my system here, but I
> > will
> > > > > > say that the rendering of the scale bar is pretty wacky due to
> > > > > > weaknesses in the scheme I used for setting cylinder radii for
> > > > OptiX
> > > > > > when drawing lines in VMD 1.9.2, something that still needs
> > more
> > > > work.
> > > > > > Can you post the error message that VMD prints?
> > > > > > Without the error it's hard to say what's going on there for
> > you.
> > > > > >
> > > > > > > 2. The general fact TachyonOptix will no more work
> > > > without
> > > > > > > restarting VMD, if it has crashed once.
> > > > > >
> > > > > > It depends. If the OptiX runtime runs out of GPU memory or
> > other
> > > > > > scenarios that it can't bail out of, it will terminate
> > rendering
> > > > and
> > > > > > usually destroy the OptiX context on its way down. In some of
> > > > these
> > > > > > cases,
> > > > > > the state of the CUDA context also gets destroyed, and VMD is
> > not
> > > > able
> > > > > > to
> > > > > > recover it. There are also a lot of cases where VMD does
> > recover
> > > > from
> > > > > > less serious issues, but unfortunately, I'd say that running
> > the
> > > > GPU
> > > > > > out
> > > > > > of memory is one of the more common problems, particularly on a
> > > > machine
> > > > > > where other graphical apps are competing for resources (e.g.
> > Google
> > > > > > Chrome,
> > > > > > a surprisingly resource hungry application, in terms of GPU
> > > > memory...)
> > > > > >
> > > > > > Cheers,
> > > > > > John
> > > > > >
> > > > > >
> > > > > > > Norman Geist.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > From: owner-vmd-l_at_ks.uiuc.edu [mailto:owner-vmd-
> > l_at_ks.uiuc.edu]
> > > > On
> > > > > > Behalf
> > > > > > > Of Tristan Croll
> > > > > > > Sent: Wednesday, February 11, 2015 12:15 PM
> > > > > > > To: vmd-l_at_ks.uiuc.edu
> > > > > > > Subject: vmd-l: Handful of rendering issues
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 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.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > - 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?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > - When using the interactive renderer, closing the
> > rendering
> > > > > > window with
> > > > > > > the mouse rather than pressing Esc or q crashes VMD.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > - 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.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 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
> > > > > > http://www.ks.uiuc.edu/~johns/ Phone: 217-244-3349
> > > > > > http://www.ks.uiuc.edu/Research/vmd/
> > > >
> > > > --
> > > > NIH Center for Macromolecular Modeling and Bioinformatics
> > > > Beckman Institute for Advanced Science and Technology
> > > > University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
> > > > http://www.ks.uiuc.edu/~johns/ Phone: 217-244-3349
> > > > http://www.ks.uiuc.edu/Research/vmd/
> >
> > --
> > NIH Center for Macromolecular Modeling and Bioinformatics
> > Beckman Institute for Advanced Science and Technology
> > University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
> > http://www.ks.uiuc.edu/~johns/ Phone: 217-244-3349
> > http://www.ks.uiuc.edu/Research/vmd/ 

-- 
NIH Center for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
http://www.ks.uiuc.edu/~johns/           Phone: 217-244-3349
http://www.ks.uiuc.edu/Research/vmd/