Silicon Graphics, Inc., (SGI) has introduced a new Applications Programming Interface (API) for visualization work on very large data sets. Named OpenGL Optimizer, it is intended to improve the rendering and interactivity of CAD/CAM/CAE data sets. In effect, it permits the programmer to visualize a forest without wasting database and computing capacity on displaying in full detail every branch, twig and leaf of all the trees. According to an SGI release, it "improves visualization performance by an average of two to ten times over applications available in the marketplace today." It is aimed in particular at the growing demand for digital prototyping, in which computer simulations display a part or other engineering project so authoritatively that the time-consuming, expensive process of building a physical prototype can be skipped. The most frequently-cited example of digital prototyping is its use in the design of the Boeing 777. Janet Matsuda, manager for emerging markets and technology at SGI, explained in an interview with HPCwire that Boeing developed its own algorithms for the 777. OpenGL Optimizer provides standardized tools that permits software developers to concentrate on the unique features of their program without taking too much time on the underlying graphics apparatus. PROPOSED FOR CONSIDERATION AS STANDARD The Optimizer sits on top of OpenGL, a 3D graphics API developed by SGI that has long been in wide use within the viz biz. In February, SGI joined with other firms in announcing the intention to form a standards committee responsible for defining an open, standard API for rendering CAD and analysis data that would be based on Open GL. In announcing Open GL Optimizer, SGI also revealed that the new product would also be offered to the proposed standards committee. Meanwhile, like OpenGL, the Optimizer will be licensed by SGI to software developers, hardware manufacturers, and users. Matsuda said that this is not intended to be a major profit center for SGI. The objective is to provide a tool that makes it easy to take advantage of SGI hardware, but OpenGL and the Optimizer are hardware- and vendor-independent. "Any API needs to be open and needs to be standard," she said. HARNESSES, OCCLUDED CULLING, NURBS, AND TESSELATION Specific features of the OpenGL Optimizer include: --Easier adaptation to multiprocessor systems. This is accomplished through a feature known as a "multiprocessor harness." An SGI backgrounder commented: "Though multiprocessor machines are becoming more common, few applications take advantage of this extra power because developing multiprocessor applications is very difficult...With no prior experience necessary, developers [using the Optimizer] can build applications that use all available processors to maximize the optimization of large visual databases." --Data simplification: multiple levels of detail are provided, making it easier to display distant objects with less detail; --Generalized culling (deleting objects that are not in view in a specific visualization). It includes occlusion culling, permitting developers to remove objects that are hidden by other objects. Matsuda said that this is the first commercial implementation of occlusion culling; --Improved tessellation (the process of displaying surfaces as polygons that can be manipulated by the graphics engine). As in the variable grids that are widely used in structural design and other fields, the Optimizer makes it possible to provide denser tessellation for curved surfaces while flat surfaces are tessellated more sparsely (that is, the triangles are bigger and fewer). Optimal polygonal surfaces are generated from trimmed NURB definitions. (A NURB is not a nerd in a suburb, but a non-uniform relational n-spline, a mathematical means to define a surface. In addition the Optimizer provides fast database loading and paging, which permits work with databases that are too large to fit on active memory in one gulp. The OpenGL Optimizer was developed after years of consultation and cooperation with independent software developers and other viz biz constituents. It is the first in a series of APIs for use with Open GL that will be aimed at specific vertical markets. An SGI briefing note said that "Although hardware graphic performance improves steadily, innovations and software technology are necessary to yield the performance improvements end users demand." ---------------------------- Norris Parker Smith is a journalist who specializes in HPC and high bandwidth communications. Reader comments are welcome.