By Eric Keller

Scientific animation is a great source of work, and also a great opportunity to flex your creative muscle. It's often a challenge to create something that is simultaneously instructive, visually engaging, and scientifically accurate. However, accuracy in scientific animations is a tricky thing. More often than not, accuracy means creating a non-misleading visual metaphor rather than a perfect atom-for-atom representation. Many times this translates into sacrificing realism for visual and conceptual clarity. That being said, when the situation does call for accuracy in the form of a molecular model, it's good to know that you can achieve this in Maya fairly painlessly, with the help of a few scripts, some free applications, and enough artistic license as the situation will allow.

This tutorial is broken down into several mini-tutorials designed to give you some techniques to build on when bringing macromolecular data into Maya. Specifically, we'll be working with the ever-popular, and often misrepresented, DNA. Of course these techniques can also be used on any of the thousands of molecules and proteins whose structure is freely available online at the Protein Data Bank website (www.rcsb.org/pdb/).

Most of the time the DNA depicted in movies, on TV, and even in publications, is wrong. DNA is often portrayed as a simple twisted ladder. Other times its structure is shown twisting to the left instead of to the right, or its has too many or too few nucleotides per bend. Sometimes it is shown with some horrible combination of all three mistakes. The structure of DNA is very important -- so important, in fact, that it earned James Watson and Francis Crick a Nobel Prize for discovering it. Think of it this way: you wouldn't throw an F-16 flying backwards in to a World War 2 movie would you? So why be just as careless with the way you represent DNA? As an animator, you are responsible for correctly representing DNA's structure; fortunately, this doesn't require a Ph.D. By bringing in the actual DNA crystallography data from the protein databank, you can start out with the real McCoy and be assured that your final DNA animation should turn out to be correct.

OK, let's get to it...
Here's what you need to complete this tutorial:

1) Maya 6.0+ any platform (I believe any platform should work, and I've tested this on NT, XP, and OSX)

2) These MEL scripts:

- pdbReader.mel v1.4 by Tom Doeden available on highend3d.com.

- jPivToParticle.mel by Julian Mann available on highend3d.com.

- particleDeformationPoly.mel by Alex Bigott but only if you're using Maya 5.0 or earlier available on highend3d.com.

- ballAndStick.mel by Geordie Martinez available at www.negative13.com

3) One of these (free) programs:

- Chime (www.mdl.com/downloads/downloadable/)
- RasMol (www.umass.edu/microbio/rasmol/)
- Protein Explorer (https://molvis.sdsc.edu/protexpl/frntdoor.htm)
- RasMac (https://mc2.cchem.berkeley.edu/Rasmol/)
- PyMol9 (https://pymol.sourceforge.net/).

4) A PDB file of DNA

5) This website:

- www.rcsb.org/pdb/


6) And an intermediate level understanding of Maya, especially regarding installing and using MEL scripts and some experience with dynamics. Knowing how to write MEL scripts is not necessary.