Planetside was developed by Psygnosis.
Back in 1992 CDROM's were showing up on PC's and "interactive movies" like "Dragon's Lair" seemed to point the way forward in interactve games. Planetside used a technique of scrolling pre-rendered landscapes which were originally created using fractal equations. Planetside was never released as far as I know but it shows one of the directions that seemed promising at the time. This one never hit the shelves but it looked good ... interactive CD... mmmmm! The concept sounded like "Cyberia". Basically a scrolling shooter, impressive looking at the time but not a sim as we know and love them.
From a preview in "The One" 1991:
PC CDROM - Early 1992
CDTV - Early 1992
Potentiallly the most far reaching and ground-breaking flight simulation featured here, Planetside (working title) is the culmination of Psygnosis' experimental work with CD based games.
The photorealistic images (using fractals and raytraced graphics) in the current demonstration running on CDTV look more like a movie than a computer game. In fact, 'Planetside' is one of the first 'proper' interactive movies to appear on the scene.
"We're more likely to make a good interactive product than say warner Brothers or Columbia" says Psygnosis co-founder Ian Hetherington. Even the flow of the game feels more lie a film - with close up and long range shots of the action."