Single Pass Instanced is a technical term that is extremely important in game graphics rendering and optimization (technical art). In VR rendering, an optimization technology that combines the drawing processing for the left and right eyes (Draw Call) into one call, and uses GPU hardware instancing to quickly draw images for both eyes at once.
Real-world analogy: When making lunches for twins, instead of making each one one by one, you can pack side dishes into two bento boxes at the same time using both hands, making it super efficient
Single Pass Instance is ``When preparing a bento (video) for children with twins (left and right eyes), instead of completing the first box and then making the second one from scratch (Multi-Pass), you line up two bento boxes in front of you and use both hands to simultaneously pack the side dishes in the same layout.'' Since the command to ``make (draw) a lunch box'' is sent from the CPU only once, the load on the CPU is dramatically reduced by nearly half, making it possible to create a surprisingly smooth and comfortable VR world even on slow-processing mobile VR devices.
Figure: Infographic that clearly illustrates the basic processing flow and mechanism of Single Pass Instanced in Japanese notation
Detailed mechanism and operating principle
From XR Plug-in Management in Project Settings, change the Stereo Rendering Mode of the target device to "Single Pass Instanced (or Multiview)".