From: Axel Kohlmeyer (
Date: Tue Feb 21 2012 - 18:29:19 CST

On Tue, Feb 21, 2012 at 6:22 PM, Diego Enry Barreto Gomes
<> wrote:
> Hi list,
> I was wondering if the developers could recommend a strategies to:
> 1) Render the frames
>        - Which raytracer, can any of the available benefit from GPUs ?

there is no general recommendation. which raytracer
is the best depends very importantly on what you want
to show and how. sometimes, there is no significant benefit
from using a raytracer over snapshots of the OpenGL window;
sometimes that is a lot. the (discontinued, IIRC) "gelato"
renderer is the only that is known to have working GPU support.
VMD supports some file formats that can be imported by
a large variety of raytracers.

> 2) Make the movie
>        - Which codec to use.

depends on platform, availability and hardware.
also, it is independent from VMD. anything that
accepts a sequence of snapshot images can
be used.

>        - Are there optimal resolutions ?

impossible to answer in all generality.
a suitable resolution depends on what
you want to show and how. for some
formats and target uses, the resolution
is predetermined (e.g. 1080p HD videos)

>        - What kind of tricks can we use to reduce file size while keeping a crystal clear animation. (reduce color space ? remove background ? H/W ratio )

depends on the codec and what you want to show.
hard contrasts compress badly, but smoothed images
look washed out. it helps to use "dirty" colors, and
particularly lots of red should be avoided. whatever
you do, it will be a compromise. i suggest you
start from your technical boundary conditions and
experiment. i have not seen a case where some
experimentation was needed. every time i do a
movie with VMD, things are a bit different.


> Diego

Dr. Axel Kohlmeyer
College of Science and Technology
Temple University, Philadelphia PA, USA.