high impact

SGI High IMPACT Graphics (1995)

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SGI Indigo2 IMPACT systems were the best workstations for game development and other activities involving textured 3D rendering in 1995. My system is equipped with High IMPACT Graphics, which is a two-card solution with a dedicated geometry engine (one million triangles/s), raster engine with two pixel processors (two pixel per cycle, 60-70 textured Mpixels/s), 12MB of pixel memory and a single texture-mapping unit with its own 1MB of texture memory.

The high-end option was called Maximum IMPACT Graphics. It took three slots in the computer and doubled the rasterisation performance by using exactly the same principle that was later used by 3Dfx Voodoo2 SLI (scan line interleaving).

The 3D performance of SGI Indigo2 IMPACT was years ahead of PCs and other workstations. In fact, 3Dfx Voodoo2, the best gaming 3D accelerator for PCs in 1998, had similar performance to High IMPACT graphics but unlike the IMPACT series, it didn’t support windowed rendering, 32-bit color precision and high resolutions.

The last two photos show Indigo2 IMPACT systems during the development of Final Fantasy VII (source: Sony press kit).

GPUbench results – compare the SGI Maximum IMPACT performance with other 3D accelerators of the same era.

LightWave 3D Running on SGI Indigo2

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LightWave 3D started its life on Amiga as a part of the NewTek’s Video Toaster editing system. It evolved in a good stand-alone 3D modeling software and was very popular. However, when Commodore filed for bankruptcy (1994) nobody in the professional market believed in bright future of Amiga. NewTek needed to find a different OS for its products which resulted in support for Windows NT (x86, Alpha) and SGI IRIX (MIPS).

LightWave on SGI was not a very long story. There were only few versions released. The main problem was in price/performance ratio. SGI hardware was expensive and usually it didn’t make much sense to buy it for generic software that is also available for other CPU/OS platforms. LightWave offered way more performance for the same price on Alpha-based Windows NT workstations which was a preferred option for some time. One year later the market shifted to Intel Pentium Pro CPUs with similar performance and broader software support (Windows NT could run only 16bit Intel-x86 software on Alpha).

I have LightWave 3D 5.6 installed on SGI Indigo2 with 250-MHz MIPS R4400 CPU and the rendering performance is only slightly better than on my 133-MHz Pentium MMX-based Toshiba laptop. NewTek apparently didn’t optimize the program to take advantage of SGI hardware.