James BrownIf my calculations are correct, when this baby hits 300rpm you're going to see some serious shit.
It's already slightly terrifying.
This is the current approach for reducing the horizontal field of view of the screens - a big heavy box o' slats. I'd like to make a lenticular array, but that's a whole side quest.
The black filament is surprisingly shiny. My first attempt turned out to be a light pipe, and didn't restrict the view. In this version, the slats have a zigzag profile.
It’s very unbalanced with only one collimator attached, so I’m spinning it too slowly for persistence of vision. But I’m sort of able to convince myself I’m seeing depth. There’s a lot of mechanical stuff I need to do before I can start cranking it up.
I have a habit of building displays that are just a confusing flickery mess on video.
The slat based collimators are such a pain, I've decided to go for it and try making lenses instead. I think a 3D printed mould will be good enough - the layer height is very much smaller than the LED size, and a bit of scattering is actually desirable. I'm printing this vertically so the lens profile gets the high resolution. It's going to be precarious when it reaches the top.
I had to turn the print 90 degrees - it wiggles rapidly doing the lens profiles, and when that was on the bed slinging axis it shook the whole room. It's a lot less dramatic when it's just moving the head.
I think I can live with it. I printed it vase mode for speed, so I was expecting it to need a stiffer structure to hold it flat.
I did have another swing at it. The first one I’d hoped to slip intact around a stiffer carrier. This one I made wider, and corrugated, so it printed better.
How can I be out of silicone?
Following a series of poor decisions, I now have both a mould and a vacuum chamber coated in uncured silicone.
Well I got a lens out of it in the end. It does make it more directional, but there’s more light off axis than I need.
I went back to the slats, and finally got all the bits hooked up together.
It sort of works?
You can see what's going on a bit more clearly with a simpler shape. It looks better when you can use both eyes on it!
The depth is smeared more than I want because the collimators are too shallow (because I don't like prints that take more than 16 hours to complete). I want to make them tighter, and spin the whole thing faster to compensate.
The nice thing about these LED panels is that they're very high framerate (and cheap!). I'm updating these at 1.5 KHz - with 3 of them in a ring, that's 4.5 KHz. Just driven in software from a (somewhat dizzy) Raspberry Pi.
Just realised that I can increase the resolution by progressively offsetting each panel by 1/3 the LED pitch.
Making parts for this has been a real saga, so while I wait for a faster printer to arrive I tried removing the collimators and running it as a swept volume display. Now I’m thinking maybe that’s what I should have built in the first place.
The thing I've been trying to make creates its 3D effect by displaying a whole different view in every direction, which means it can handle occlusion and fancy lighting at the cost of vertical parallax.
To turn that setup into a swept volume (where it's lighting up the LEDs according to where they are in space - full 3D, but glowy and transparent) I keep everything but the collimators, and just render each view with the near & far clip planes set really close together.
I'll probably make two displays now - finish off the autostereoscopic one, but then rearrange the geometry so that I can sweep through more than just a thickish-walled cylinder.
Leonard Ritter@ancientjames excellent work. swept volume sounds like the way forward. though just going by the integral of the coverage, LEDs in the center will have a much higher spatial resolution than the LEDs further out. i've dreamt up alternate "mill"-like setups where the distribution is better/ideal. but they need more space, and i don't know if a treadmill could be moved fast enough.
ftg@ancientjames
Is that glass or some plastic?
Is that glass or some plastic?
@ftg plastic.
Keir Rice ⬢
Andrew Gallagher@ancientjames a courageous decision to operate that without a safety cage… 😱😱😱
@andrewg I do a safety squint.
seachangedI want to hear the audio channel when I see this, to more fully apprehend the simultaneous sense of wonder and fear of physical injury this new medium might evoke.
Why not vertical sections of a cylinder, instead of flat panels fitted into a prismatic column? Might not the driver arithmetic be simpler, regarding LED drive time at the edges of panels versus uniform drive time across a cylinder section?
@seachanged a cylinder would generate all the rays through the axis. By spinning a flat panel (or several) I’m generating multiple rays for each column.
As for the sound - between the repurposed line trimmer motor, thin plastic base & 3D printed gear, it’s *offensively* noisy. Imagine gravel in a blender.
As for the sound - between the repurposed line trimmer motor, thin plastic base & 3D printed gear, it’s *offensively* noisy. Imagine gravel in a blender.
Hans Gerwitz@ancientjames I’m not quite sure how you’re going to extend the NBTV standard for 3D.
Jason, Human, Average 
Matt Gagle@ancientjames “progress”
Nixie@ancientjames "siligone"
I'll see myself out.
otto9otto@ancientjames
Silicone grease and adhesive are semi-transparent. Depending on your application, you could try other adhesives such as epoxy.
Silicone grease and adhesive are semi-transparent. Depending on your application, you could try other adhesives such as epoxy.
Shambolic Matter@ancientjames noooooooooooooooo!
:David Campey@ancientjames humbug! Feeling the vibes, here are a bunch of rafts and not one print yet. Struggling with filament jams, and adhesion, and a blocked nozzle 🤣
Nathan Matsuda@ancientjames can you print short molds and stack them, or cast short lenses and stack them? the seam will also be on the low res / scattering axis
@ancientjames seems like a good project for a coreXY printer instead of a bed slinger.
@mgagle Or a CNC machine
@ancientjames that too. Depends on the budget 😅
@mgagle That's my problem - I keep thinking, ooh those are pretty cheap these days. Then upping the spec a little... a little more... oh, those things are too expensive.
@ancientjames “what’s a few upgrades? If I add this feature, it’ll save me 10 minutes!” Yeah, it starts with an ender 3 for $100, and the next thing you know you’re pricing industrial CNCs for tens of thousands.
Martyn@mgagle @ancientjames I just got a corexy conversion kit for the ender3, looks nice, about to install it. Will come back to this thread once it's running if you are interested?
@ancientjames @martyn same here! I recently got the base Bambu Lab model and it’s really put my Enders out of business.
Ted Mielczarek@ancientjames are the slow-motion cameras on modern smartphones enough to mitigate that, or in this case does it ruin the persistence of vision effect making it meaningless?
@tedmielczarek yes, a longer exposure will help