Realistic Dynamic Projection Mapping Using Real-Time Ray Tracing

[wiraxbox363]

Takashi Nomoto, Ryo Koishihara, and Yoshihiro Watanabe. Realistic Dynamic Projection Mapping Using Real-Time Ray Tracing, ACM SIGGRAPH 2020, Emerging Technologies, August 2020.

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Hi Chief Blur Buster, what do you think of this new technology, do you think it will be implemented in games?

[Chief Blur Buster]

This is a technique of Temporally Dense Raytracing -- at very high frame rates, low raycounts are very good.

NVIDIA has a page about this technique with a companion www.240hz.org website, as well as a peer reviewed paper (that also credits Blur Busters on Page 2, go check it out!)

1000Hz is extremely useful for projection mapping, and DLP chips arefast enough to do 1000Hz at monochrome or reduced color depths.

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As a caveat, DLP is not ideal for single-frame full-color-depth frames at ultra high Hz, so there's some compromises made (reduced color depth per single refresh cycle, using temporals to get full color depth). It takes really high-Hz DLP chips (like new 2880Hz chips) combined with 3-chip operation, to get good color depth at high-Hz. Like the new Christie projector that can do 480Hz at usable color depth.

Most of this is DLP for now, since they are the oldest digital technology easily capable of native ultra-high-Hz operation, although historically at ultra-low-color-depths per Hz. DLPs historically need ultra-high Hz (typically 1440Hz) because it takes 24 refresh cycles of 1-bit, to generate 24-bit color at 60Hz.

But this can create temporal-color-separation artifacts during color-sequential operation (aka rainbow artifacts), which is prone to problems during the Vicious Cycle Effect. Without speeding up the color sequential behavior, the color refresh rate can become a lower frequency than the monochrome refresh rate.