In this tutorial, we’ll explore different methods for modeling, rigging, and animating DNA. There are many ways to approach this macromolecule in Maya and each has its merits depending on what the model will be used for in your scene. We’ll start with a simple ‘plank’ DNA model that is roughly based on what is known about the molecule’s proportions, and then look at different ways to deform it. Next we’ll import a PDB coordinate set for B-DNA and experiment with different representations using particles. These first two methods assume that the helix does not need to unwind and melt. Finally, we’ll go over a programmatic approach to building DNA using PDB data for a single base pair – this method will allow us to twist and unzip the double helix.

Modeling plank DNA
In this first exercise, we’ll create a stand-in model for B-DNA that could be useful in schematic animations where atomic resolution is not required and melting of the double helix is not necessary. Here’s a quick overview of the process: 1) model a base pair with polygons, 2) animate its rotation and elevation to use the ‘animated snapshot’ tool, 3) create 2 NURBS curves slightly offset from the base pair, 4) use the ‘animated sweep’ tool to extrude those circles and create the backbone and finally 5) ‘duplicate special’ to create additional helical turns to the model prior to rigging.

Although we’ve reviewed B-DNA’s characteristics above, let’s also have a PDB-derived cartoon model in our scene to make sure we have the right proportions as we go through the modeling process. Go to www.molecularmovies.org/learning and download the supporting files for this tutorial.

Download pdf DNA: variations on a theme in Maya