Virtual reel technology is a system used in modern slot machines to control the odds of winning. Traditionally, slot machines had physical reels with symbols printed on them. The random number generator (RNG) would determine which symbols landed on the payline.
With virtual reel technology, the RNG is programmed to select from more virtual reel stops than the physical reel has. This allows the game designers to decrease the odds of hitting winning symbol combinations, even if the physical reels have the same number of stops. In effect, the virtual reel system enables slot machines to offer larger jackpots and lower overall payout percentages, while still maintaining the appearance of a traditional reel-based slot. This technology helps casinos control the mathematical house edge on their slot games.