3Dfx has slapped a patent infringement suit on rival 3D graphics specialist Nvidia. The suit alleges Nvidia has incorporated 3Dfx's multi-texturing technology in its own products. The 3Dfx suit contends that Nvidia's Riva TNT chip-set uses technology it developed in 1996 that allows multiple textures to be applied to a single 3D object. The developer claims it attempted to reach a negotiated settlement with Nvidia, but the attempt failed. "We see litigation as an unfortunate last resort," said 3Dfx president and CEO Greg Ballard. This is the third time Nvidia has been accused of infringing patents this year. Silicon Graphics sued the company in April, and S3 did the same in May. Nvidia has achieved many plaudits from the graphics and games industries for its products, largely for the higher performance and functionality it offer. All of which has helped the company oust 3Dfx from the games world's 'flavour of the month' slot. Interestingly, Nvidia also helped Microsoft in the development of the DirectX 6.0 3D graphics component Direct3D. Its contribution: adding multi-texturing to the games-oriented API. As Direct3D is designed to provide a common link between games software and graphics acceleration cards, to an extent it dictates how the cards work. In other words, any card that supports Direct3D 6.0's multi-texturing must ultimately be based on Nvidia multi-texturing technology. Which, allegedly, it copied from 3Dfx. So, support multi-texturing through Direct3D 6.0 and your card is in danger of infringing 3Dfx's patents too. Microsoft is already recommending Nvidia's Riva TNT as the DirectX 6.0 graphics reference platform. "As the most complete implementation of the DirectX 6.0 feature-set, Nvidia's RIVA TNT serves as the optimal reference platform for our developers," said Charles Boyd, Microsoft programme manager for Direct3D, earlier this month. Neither Nvidia nor Microsoft has yet responded to 3Dfx's allegations. ®