Maybe one of these? https://www.gamedev.net/forums/topic/297894-good-3d-browser-based-game-engine/ https://www.gamedev.net/forums/topic/297894-good-3d-browser-.

Maybe one of these? https://www.gamedev.net/forums/topic/297894-good-3d-browser-based-game-engine/ https://www.gamedev.net/forums/topic/297894-good-3d-browser-... Your description also made me think of babylon js, but that was later. Also maybe java applets?