VMD-L Mailing List

From: Boris Steipe (boris.steipe_at_utoronto.ca)
Date: Tue Oct 12 2010 - 19:07:16 CDT

However some of QuteMol's techniques like borders and halos would be nice to have in any case, even if only for the renderer. And AO for static structures within VMD would be a plus as well - many of us use VMD for visualizing static structures and MSMS and APBS aren't real-time for trajectories either. It's actually quite convincing what QuteMol achieves and I can see how that would be useful in presentations/publications.

$ 0.02
Cheers,
Boris

On 2010-10-12, at 5:24 PM, John Stone wrote:

>
> Hi,
> Indeed, it would be nice to have real-time AO for VMD, but as you
> might imagine, it is MUCH harder to do so for a program that allows
> trajectory animation (e.g. VMD) than for a program that only displays
> static structures like QuteMol. QuteMol does a pre-processing step to
> compute it's AO, and from that point on it can re-use the precomputed
> result. This only works if the atoms aren't allowed to move. Also, the
> specific techniques used in QuteMol only work for spheres, and not for
> arbitatry triangulated or volumetric geometry as is the case in VMD.
>
> Although it isn't practical to apply the QuteMol techniques to a program
> like VMD, there are still some AO approaches that can be made to work,
> with some significant effort. Screen-space ambient occlusion (SSAO)
> might be one way to implement real-time AO for VMD. SSAO has varous
> flaws vs. true world space ambient occlusion, but it can be made to
> run fast even with dynamically changing geometry. SSAO is used in a
> number of video games now, so that demonstrates that it can be made
> feasible with work... The main issue with SSAO and related techniques
> is that they require multiple rendering passes, which adds significant
> computational cost and complexity to the VMD rendering code beyond what
> people are used to now. I will likely implement multipass rendering
> in VMD for some other features like transparency based on depth-peeling
> and possibly for some volume rendering techniques, so once that's in
> place SSAO becomes much easier to implement.
>
> Anyway, I'm interested in supporting real-time AO in VMD, we just have
> to pick an algorithm that works reasonably well and doesn't have such a
> high performance cost that it isn't usable on mid-range GPUs. It has been
> on my TODO list for a while, but I have a long TODO list presently...
>
> Cheers,
> John Stone
> vmd_at_ks.uiuc.edu
>
> On Tue, Oct 12, 2010 at 10:54:00PM +0200, Ajasja Ljubeti?? wrote:
>> Dear VMD developers,
>> Just out of curiosity -- are there plans for real-time ambient ambient
>> occlusion lighting along the lines of QuteMol?
>> I was playing around whit this program today and
>> IA immediatelyA wishedA for the power of selectA macrosA and different
>> representations of VMD:)
>> Best regards,
>> Ajasja LjubetiA:*,
>> youngA researcher,A
>> Department of solid state physics,
>> Institute JoAA 3/4ef AA tefan,
>
> --
> NIH Resource for Macromolecular Modeling and Bioinformatics
> Beckman Institute for Advanced Science and Technology
> University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
> Email: johns_at_ks.uiuc.edu Phone: 217-244-3349
> WWW: http://www.ks.uiuc.edu/~johns/ Fax: 217-244-6078