“Lights, camera, action!” might have been the call when recording back in the day, but for an awesome three-dimensional viewing experience, you might try yelling “Mist, Mirrors, Laser!” and following in the footsteps of [Ancient]’s latest adventure in voxel displays, which is also embedded below.
He starts with a naive demonstration: take a laser projector and toss an image into a flat cloud of mist. That demonstrates that yes, the mist does resolve an image, and that the viewing angle is very poor– that is, brightness drops off sharply when you’re out of line from the projector. In this case, that’s a good thing! It means more angles can be projected into that mist for a three-dimensional, hologram effect.
The optical train gets folded up, probably to make this fit on a tabletop: first, an array of flat mirrors in front of the projector splits the image from the projector into multiple viewpoints, which are each bounced to a second flat mirror that sends the image into the fog bank.
Some might call the resulting image a hologram; others might complain that that’s technically something totally different, and that this volumetric display is just all smoke and mirrors. We can hope that [Ancient] sees fit to share more details, like the software stack needed to generate the video feed– though it’s likely using a version of the same software as his last volumetric display, which used the same laser but whose point cloud was made from a bubblegram rather than an actual cloud. With a lot more points, though, the resolution is amazing in comparison, at the cost of appearing fuzzy at the edges. Unfortunately, we do not see the display in this demo run DOOM, as one of his previous projects did.
This video is more of a demo than a how-to, but it’s a heck of an impressive demo. If you don’t feel like watching the assembly, jump right to 9:00 to be impressed. It comes across a lot better on video than in the screenshot.
It looks impressive but it’s really just all smoke and mirrors.
You win for today. Congratulations. Please treat yourself to a delicious baked good of your own choosing, take the day off, and inform your loved ones.
I’d be more impressed if it wasn’t almost the same as one of the top comments on the video.
PropDropAndRoll, is that you?
He should have projected a sphere, that probably would have looked convincing.
Well he did project a torus
My big question here is whether the brightness and directionality of the images persist if you look up at the image from below. The video shows the camera basically moving in a plane such that the projected light-paths for each mirror intercept the lens after passing through the mist. I.E. Without the mist, you wouldn’t see Slimer, but you would see a bright light from the projector because it’s pointed right at the camera, adjusting for the complex light path.
If Ancient keeps playing with freespace image projection, I would love to see him play around with the complex lens that he used for light field displays last year. The lens he played with might not work for a projector, but there’s no doubt something he can do there.
I’m confused how the lights from all angles aren’t intersecting each other. I would expect Slimer’s tongue to be a red streak or star throughout the mist column
laser projector. While the light is “mixing” the viewing angle is tight so you dont really see the projections you are not aligned with.
Mentioned in the article; limited angle of view of each image due to how the cloud is diffusing light.
Semi-unrelated: I saw a claim decades ago that it was possible to project onto a smoothly falling “nitrogen curtain”, taking advantage of the difference in index of refraction, to produce a (flat) image with no visible support. Never found confirmation or details of that. Obvious concerns about maintaining safe ventilation without disrupting the “screen”, even if it does work, but I’d like to see more detail.
I’d also like to see someone scale up this mist projection technique…
Ever use combustible gases?
I would want a figure with UV paint to stand behind the mist…a fire-eater. Dimmer switch makes that figure “emerge” and set fire to the mist dragon holo’ and walk through it.
It projects Doom sprites!