Incorporating VRML
molecular images in Powerpoint presentations
Background
VRML files
allow real-time manipulation of graphic objects, and since some molecular
modeling and rendering programs provide for VRML output, there is the
opportunity to have presentations that permit real-time manipulations of these
objects. Powerpoint is a commonly used
program for seminars, and the question arises as to how to incorporate VRML
files of molecular objects into Powerpoint presentations. After much time and anguish, I have
identified all the relevant programs and utilities to allow the incorporation
of VRML files into Powerpoint presentations.
Here is how to do it:
1. Producing a VRML file from a PDB file (e.g.
protein structure)
Not many
PDB modeling or rendering programs provide for VRML output; one program that
does is DS Visualizer by Accelrys. This
program will allow you to read in a PDB file and render ribbon drawings,
spacefilling atom representations, etc. and save in VRML format. This is (was) a free version that can be
downloaded from:
http://accelrys.com/products/discovery-studio/visualization/discovery-studio-visualizer.html
The VRML
output from this program is in VRML1.0 format.
With regard to plug-ins to view VRML files in Powerpoint, the most
reliable ones I have found work best with VRML2.0 files. This brings us to the next point:
2. Converting VRML1.0 to VRML2.0 formats
There are a
few converters available to permit reading VRML1.0 files and writing VRML2.0
files. Unfortunately, most of the ones I
tried did not work well (i.e. did not faithfully convert colors, etc.). In fact, I only found one that worked well:
This zipped
file contains two files: a command line executable and a DDL file. Unzip the files and place in a working
directory. Open a command window and
give the command for the executable as follows:
vrml1tovrml2.exe
"input filename" > "output filename" (don't use the actual quotation
marks; do use the redirection symbol between the filenames - otherwise the
output file will go to the screen only).
3. Installing a VRML plugin for Powerpoint
Again,
there are a couple of these plugins available, however, not many seem to work
reliably. Many seem to have real
problems with the lighting (i.e. "headlight" command) and produce a
very dim image. I found one that worked
great, but would not retain the name of the VRML file upon closing powerpoint. One that does work well is the Cortona viewer
from ParallelGraphics:
http://www.parallelgraphics.com/products/cortona/
Once
installed you can give the "insert object" command in Powerpoint and
one of the listed objects will be "ParallelGraphics Cortona
Control". Insert this object, right
click it, select "Properties" and a window will open with a list of
options. Select "Scene", click
the "…" button and browse for the VRML file to be inserted. Close the options window and view the
Powerpoint slide (as slideshow). The
VRML object can now be manipulated within the Powerpoint presentation!
One final
issue relates to the path for the VRML file and transferring the Powerpoint
presentation to another computer (e.g. laptop).
The location of the VRML file in the "Scene" parameter will
have a format of "file//driveletter:/foldername(s)/filename". This will be true even if you just type the
filename (and it is in the local directory).
Thus, you need to be sure the drive and folder names/structure is
identical between computers (or edit the presentation on the new computer to
identify the new location for the VRML files).
Final
Notes
If you
right click on the VRML window during a slide show in Powerpoint, you will
bring up the "Preferences" dialog box. If you click "Skin" and then select
"CAD", an extremely useful set of buttons will be displayed that is
most appropriate for manipulating molecules.
Dr. Michael
Blaber 2003