Scalability of terrain visualization in large virtual environments

Only recently one is able to build dedicated low cost PC's for simulation or visualization. The cost/effectiveness has been substantially improved by the fact that 3D accelerators (a piece of hardware which implements part of a graphics pipeline) marketed as toys for garners are in fact high-end graphics hardware with all the required professional features for high end visualization. Such a game" card is used increasingly by professionals, which may be not so surprising when you compare the performance of these 'gaming cards' with the professional systems of a few years ago. Together with the increased computing power of a PC and other developments, for instance the usability of OpenGL on Windows, the PC has become a viable platform for simulation and visualization. As a consequence applications which before required a workstation or even more powerful hardware, can now be run on a PC at fairly low costs. Of course the capabilities of top non-PC systems are increasing too and their performance is still way beyond the capabilities of a PC. To conclude one may say that the use and development of visualization and/or simulation systems has become more accessible. Also it is concluded that, that depending on aim and budget, there is a choice from an increasing range of computing hardware. Unfortunately, choosing a different hardware setup has currently a major drawback: in many cases it will be necessary to rework or even rewrite large parts of the software to make use of the increased (or decreased) computing power. A software system optimized for a low-end hardware target platform will not be directly usable on a high-end Silicon Graphics (SG) multiprocessor system graphics computer. For example, when porting a simulation software system from a Pentium PC to a SG graphics workstation chances are that the Pentium computer will still have a better performance measured in Frames per Second (FPS) than the SG This may be due to system specific optimizations, leaving the SG not using its full hardware potential. This problem not only occurs when moving between low and high-end computing hardware but also between generations of both low and high-end machines. Changing the aim of a simulator is another common cause in making software obsolete, leading to the necessity of having to rewrite simulator software. For example, a flight simulator may have been optimally designed and built for the visualization of airplanes. As an effect it may render the architecture obsolete when it is required to simulate helicopters as well, resulting in a loss of investment. Since software development is an expensive and/or time-consuming affair it is preferable to avoid this problem in the first place. Required, then, is a software architecture that runs as optimal as possible on different hardware platforms and is capable of accommodating simulations and/or visualizations with different purposes (flight simulation, driving simulation, walkthrough, etcetera). Such an architecture may be called a multipurpose, scalable simulation and visualization system.