Abstract
This paper describes an IBM-compatible microcomputer-based algorithm, written in Turbo C, for the animation of three-dimensional wire-frame finite element structure models on a variety of graphics devices. Since the Disk Operating System's memory addressing limitation of 640 kilobytes (KB) for a given program exists, the algorithm is implemented with a two-image animation scheme with each image stored as a portion of the entire screen in four memory buffers. The user may observe animated natural modes in elevation, plan, cross-section, and isometric views with an adjustable time delay between frame switching. As an example, the resulting algorithm is utilized to display natural modes of the Luling cable-stayed bridge. Discussions are made on the effect of different graphics devices on the animation process with regards to resolution, color versus black and white, memory requirements, and runtime flicker. The algorithm has proved reliable and efficient in its use, and above all, a great tool for engineers to quickly ascertain modal characteristics of complex structure configurations.