Installation of the Molecular Playground
The Molecular Playground uses the open source software Jmol to render animated images of molecules. Jmol loads x,y,z atom coordinates from a Protein Data Bank or other crystal or model file and renders that molecule according to a script crafted by the unit writer. When no user is present, Jmol follows that script: rotating, zooming, or cutting away to reveal a bound ligand. After a given period of time, the computer loads a new molecule and a new script and begins the process anew. When a user approaches, the software (see below) detects this and temporarily halts the script. Control is now given to the user who can rotate the molecule with the waving of a hand. When the user steps back (or stops moving), the program will wait a moment and then resume the pre-programmed script.
As seen in the photo at right, the local Playground installation consists of a projector, an infra-red (IR) illuminator, and a camera fitted with a filter that blocks visible light, but passes IR. In this way, the camera "sees" the persons playing with the image, but does not see the projected image itself. The camera tracks movement and the software then decides what to use as a trigger to tell Jmol to stop the pre-programmed animation and instead deliver "rotate" commands to Jmol.