Section 17.2.4.2. Animation

Computer-graphic molecular animations began to appear in the late 1960s. Recording directly off their vectorscope, Levinthal and colleagues in Project Mac produced a record of an interactive molecular modelling session in 1967. In the early 1970s, a number of molecular animations were produced to convey new scientific results. Wilson at UC San Diego showed vibrational modes of small molecules in a film produced frame-by-frame on a vectorscope. Parr & Polyani painstakingly filmed pen plotter drawings of space-filling diatomic molecules to animate a bimolecular chemical reaction. Sussman & Seeman produced a black-and-white vector animation of the dinucleotide UpA structure in 1972 by recording directly off a vectorscope. Seeman, Rosenberg & Meyserth produced a more ambitious molecular animation in 1973 entitled Deep Groove, which depicted the structure of double helical segment ApU CpC and its implications for more extended DNA geometry. This film was shot in colour, using a monochrome vectorscope and multiple exposures through a colour filter wheel. Around this time, Knowlton, Cherry & Gilmer at Bell Labs used early frame-buffer devices to display and animate patterns of crystal growth based upon aggregation of spheres. In the mid-1970s, Porter & Feldman had developed a scan-line based CPK representation for raster displays and had animated molecular structures, and Langridge and co-workers had taken up recording off the black-and-white vector displays then available. By the end of the 1970s, Max had produced high-quality animations of DNA using a high-resolution Dicomed film writer (Max, 1983) and Olson had used an early colour vector display from Evans and Sutherland to produce an eight-minute animation depicting the structure of tomato bushy stunt virus (Olson, 1981). By the early 1980s, animation projects became more ambitious. Olson produced large-screen OmniMax DNA and virus animation segments for Disney's EPCOT center in 1983. Max produced a red–blue stereo OmniMax film for Fujitsu entitled We Are Born of Stars, which included a continuous scene depicting the hierarchical packaging of DNA from atoms to chromosomes, based on the best current model of the time.

Computer-graphics animation has presented both great potential and significant challenges to the molecular scientist wishing to communicate the results of structural research. Animation can not only enhance the depiction of three-dimensional structure through motion stereopsis, it can show relationships through time, and demonstrate mechanism and change. The use of pans, zooms, cuts and other film techniques can effectively lead the viewer through a complex scene and focus attention on specific structures or processes. The vocabulary of film, video and animation is familiar to all, but can be a difficult language to master. While short animations showing simple rotations or transitions between molecular states, or dynamics trajectories, are now routinely made for video or web viewing, extended animations showing molecular structure and function in depth are still relatively rare. The time, tools and expertise that are required are not generally available to structural researchers.