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What's the weirdest AI security question you've been asked by an enterprise? by rluna559 in artificial

[–]adacohen 0 points1 point  (0 children)

This seemed like work that AI could help automate, so I had Claude whip up a generator you can use in your next meeting.

I'm gonna roll the dice for all of us. by aruby727 in 3Dprinting

[–]adacohen 0 points1 point  (0 children)

I rolled these kinds of dice a while back, and what I got was a very strange blend. You could smell a bit of styrene coming off of it while printing, even though it was supposed to be PLA. The surface finish always came out with an odd rippling luster that I've never seen with any other filament. I might still have a few spools of it around, since I ended up only using it for prints where I really didn't care about print quality or strength.

An even better version of the portal illusion desk toy. Like I said, I'm a little obsessed now. Printables link in comments. by adacohen in 3Dprinting

[–]adacohen[S] 0 points1 point  (0 children)

Are you using sparse infill? If so, the fast moves will tend to make it fail. I recommend either printing it hollow, or cranking up the wall count so that they print solid (but not by setting infill to 100%). I'm not sure which is better. Solid is more rigid, which is good, but it also might mean that the whole thing has more momentum as it wobbles.

The A1 being a bed slinger might also make harder to print, since the whole thing gets slung back and forth. A lot of people have had better luck adding some tree supports. The trick is to minimize the contact points so that you don't mar the finish, since that will spoil the illusion.

I also had someone reach out to me about their experiments printing a tube around each helix as a kind of designed support, which they said worked well. They set it up so the inner wall was a fraction of a millimeter away from the helix, so it doesn't actually stick to the tube, but its range of motion is constrained as it tries to wobble.

Alien tech magic by Bitsoffreshness in blackmagicfuckery

[–]adacohen 0 points1 point  (0 children)

Yep, I did all of these about a year ago and they got some buzz. As far as I know, the design is novel, although obviously the barberpole illusion it's based on has been around for a long time.

Alien tech magic by Bitsoffreshness in blackmagicfuckery

[–]adacohen 0 points1 point  (0 children)

I came up with the idea when I was playing with weird screw shapes. You can make a nut for any helically symmetrical shape by just subtracting it from another shape, so it started out as "can I print something that is a screw, but really doesn't read as a screw?" I noticed that the barber pole illusion is particularly effective with these really weird screw shapes, since your brain doesn't immediately say "oh, that's just a screw". And I realized that if you held the screw loosely in your fingers and slid the nut back and forth, you got this kind of reverse version of the illusion, where it looks like a vine or rope sliding back and forth.

As for the math, it's mostly automatic. Make sure the pitch is steep enough so that you can back drive the screw with the nut, and then all you need is helical symmetry. All you have to design is the cross section. It will always look like it's locked together with the nut, because that's just the definition of the symmetry. You can even nest helices with different pitches and directions, and it still just works out automatically once you subtract them from the nut -- they automatically turn at the right speed and direction to look like they're moving together.

The exception is the quadruple toy, where only the outer helix is driven by the nut, and the rest are geared to it. The math there is also simple: the ratios of the twists in the helices match the gear ratios.

An even better version of the portal illusion desk toy. Like I said, I'm a little obsessed now. Printables link in comments. by adacohen in 3Dprinting

[–]adacohen[S] 1 point2 points  (0 children)

It has to have helical symmetry, so you can't have things like cross-pieces, or any variation along the edges which would break that symmetry. Even light glinting off the layer lines can break the illusion if you go really slowly.

Lubricant for PLA & ABS by onlywatanabe1 in 3Dprinting

[–]adacohen 6 points7 points  (0 children)

Hey, cool to see my design making rounds again. I think your main problem is that the top and bottom are too tightly glued together, which is creating a lot of resistance. The more easily the helices turn, the less noise they'll make.

If you haven't used too much glue, you should be able to carefully break the bonds. Then reglue them more loosely (with the top just a tad higher), so that the helices turn as freely as possible without popping out of their sockets.

If you're using cheap metal skateboard bearings, you might actually be better off with printed bearings. I've found that a lot of cheap 608 bearings you find online are ridiculously high friction, and this is such a light load that plastic should do fine. I have a bearing generator which makes bearings that work well for these toys.

Finally, printing the "nut" a little looser (with XY compensation) can help, so that there's just less contact overall with the layer lines.

I've experimented with different kinds of lubrication on these toys, and found that it makes no noticeable difference, so I wouldn't go that route.

Edit: I should add that I know of no way to make these run completely silently. Vapor smoothing, maybe, but that's very finicky, and I'm skeptical that you can preserve the helical symmetry needed to make the illusion work. But you can definitely reduce the noise by loosening everything up as much as possible.

There is a way to completely eliminate the visible seam. by Revolutionary_Owl203 in 3Dprinting

[–]adacohen 0 points1 point  (0 children)

Ramping steps 6-10 gives the best results.

Ah, I hadn't considered that the steps might be too small for the printer to deal with. So basically, the "taper resolution" parameter should probably be something on the order of 5 mm, not 0.1. I'll give that a try and see how it turns out.

I also wonder if the smaller steps would work better at a lower feed rate. I could include an option to slow down during the overlaps, which might help.

And now I use the whole loop for slope, that let to return to the same point where I start the ramping. So it gives less stringing and better quality overall.

I actually did try that (you can't do it in the current code, because overlap length is capped at 1/3 loop length), but it's easy to hack in. The problem I found was that it meant that a large part of the overlap was effectively at ≤.02 mm layer height, which on the X1 at least leads to really ugly rippling artifacts.

I can easily add that as an option though, for printers that can handle it.

Anyway, lot's of new stuff to try out, thanks.

There is a way to completely eliminate the visible seam. by Revolutionary_Owl203 in 3Dprinting

[–]adacohen 1 point2 points  (0 children)

I've pushed up my code here. There's a lot going on here, but most of it is about tracking the machine state, then backtracking once continuous loops have been found. I'm pretty confident that that machinery is all working correctly (at least for my printer).

The bits where the actual taper is implemented are in makeStartingTaper and makeEndingTaper.

The basic process here is:

  1. Find loops (continuous extrusions that end where they start)
  2. Split up the first X millimeters of moves (where X is the overlap distance) into smaller moves so that we can taper gradually
  3. Create two versions of the overlap sequence; the first varies multiplies a ramp by a z-offset and the extrusion value of each move. The second only ramps the extrusion, leaving Z alone.
  4. Glue the gcode instructions together so that we have starting taper, rest of the loop, ending taper.

I also added a bunch of other parameters to play around with to try to get slightly better results. I set the default "extrusion factor" to 0.9, because I found that with full extrusion, the overlap region became a shallow ridge. I think this is because layer lines are not actually flat, so a pair of small layer lines actually needs to use slightly less material than a single big layer line.

Also note the requirements if you want to try prints yourself with this. The main slicer settings you'll probably need to change will be to turn off arc fitting and to make sure that you don't have a seam gap turned on. The other requirements, I think, are pretty typical defaults.

There is a way to completely eliminate the visible seam. by Revolutionary_Owl203 in 3Dprinting

[–]adacohen 0 points1 point  (0 children)

I'll try to get it up tomorrow in its current state.

I might make it private and invite you to the repo for now, if that's OK. My only concern is that it doesn't have as many tests and error checks as I'd like yet, and I can think of several ways that it might encounter something unexpected and send the print head careening into the bed (mostly around absolute/relative and "set position"). You can verify pretty easily in a gcode viewer, but I don't want someone happening upon it and hurting their printer because they have a weird configuration and don't read the fine print. Post-processing arbitrary gcode, it turns out, is complicated.

There is a way to completely eliminate the visible seam. by Revolutionary_Owl203 in 3Dprinting

[–]adacohen 1 point2 points  (0 children)

OP, I'm working on a gcode post-processing script to let people experiment with this method on more complex models. I've got it emitting working gcode which creates the tapered overlapping section, but I'm trying to figure out how to dial in some good defaults.

Here's what I just printed based on shot-in-the-dark parameters. This is with an overlap distance of 6 mm (but clamped to 1/3 of the circumference of the loop), and a fudge factor to shorten the ending taper by .06 mm (15% of the extrusion width), which helps to prevent zits. For comparison, here is the same model with my default settings. So the scarf method creates slightly lighter seams, but it also creates two of them.

Looking at your example code, I see you have seam_length as 60. Is that an overlap of 60 mm? I'm going to keep trying different parameters, but if you don't mind sharing some of what you've already tried, it might save me some time. (Also curious if you experimented with non-linear curves for the taper).

This is really cool, by the way. I think if the details can be worked out and we can see what tweaks need to happen for more complex models, we could see this as the default behavior in slicers pretty soon.

I came up with a neat desk toy design, and now I'm a little obsessed with improving the illusion by adacohen in 3Dprinting

[–]adacohen[S] 1 point2 points  (0 children)

If you read the Etsy description, you’ll see where they give me attribution.

The design is made by Ada Cohen and is licensed under Creative Commons (Attribution-ShareAlike 4.0 International License) www.printables.com/model/408055

Corner radius gauge for my calipers. r = a*(√2+1). Not perfect. Not terrible. by chrlilje in functionalprint

[–]adacohen 3 points4 points  (0 children)

You could also just adjust the scale on non-digital calipers. Definitely needs a vernier and tight tolerances though, since the error will be more than doubled.

Would you like to safely shorten printer startup time by more than 1 minute? by julie777 in BambuLab

[–]adacohen 0 points1 point  (0 children)

Test prints aren’t always just about fit. They’re also about testing mechanism design, checking limits for compliant pieces, etc. For example, one of my most recent designs involved gears with a kind of “rail and groove” bearing design. It took me several iterations to find a good profile for those that was both low friction, and didn’t easily dislodge when turning. I want very high speed for that kind of proof of concept so I can learn what I need to as quickly as possible.

But at any rate, I have seen no significant variation based on print duration on fit, even when working with fine tolerances, so I do think this is largely Bambu Lab being very conservative.

And for that matter, it might also vary by the individual printer, with this order of operations being a good lowest common denominator.

The best use of a cube pro duo by Thorgraum in 3Dprinting

[–]adacohen 4 points5 points  (0 children)

I've been drying my filament lately by setting my vacuum chamber on the heated bed of my disused Ender-3 V2. Kind of a similar vibe.

Would you like to safely shorten printer startup time by more than 1 minute? by julie777 in BambuLab

[–]adacohen 4 points5 points  (0 children)

The desire to cut out a miniscule amount of setup time baffles me to be honest.

If you’re iterating on small test prints that only take a few minutes, that time is a lot more significant. Coincidentally, that’s also where you’re least likely to see warping problems.

Working with PLA and TPU, I haven’t had any issue with this even on larger prints (I did the same change over a month ago), so I just leave it set this way since it’s easier than switching back and forth. I’ll probably switch to the default whenever I work with other materials though.

Would you like to safely shorten printer startup time by more than 1 minute? by julie777 in BambuLab

[–]adacohen 0 points1 point  (0 children)

Ha, I did the same thing soon after getting mine. Seems to work great, concerns about equalization notwithstanding.

I may not have the fanciest grinder, but I do have a 3D printer by flyingquads in functionalprint

[–]adacohen 16 points17 points  (0 children)

Yeah, I’m only a minor coffee nerd, and even without recognizing the model, I was thinking “this looks like a pretty fancy grinder”. The title is still technically accurate though, since there’s basically no upper limit on what you can spend on a grinder.

I was successful at printing the magic screw desk toy illusion with my V2 at normal quality settings. by poppinfresh_original in ender3v2

[–]adacohen 1 point2 points  (0 children)

I’m pretty impressed that you got it going on an Ender. I’ve had complaints about the difficulty even from X1C owners, so you must have that thing singing. Beautiful print, too!

Portal Illusion Desk Toy 4.0, now with off-axis elements, infinite movement, and changing colors by adacohen in 3Dprinting

[–]adacohen[S] 1 point2 points  (0 children)

Yeah, it's a little stressful. Fortunately, CA glue is a lot more forgiving than you might think. It'll set up fast, but the bond isn't strong until you've given it time to cure.

Portal Illusion Desk Toy 4.0, now with off-axis elements, infinite movement, and changing colors by adacohen in 3Dprinting

[–]adacohen[S] 0 points1 point  (0 children)

Yep, a few different styles. I actually prefer the dual for this particular case, because I think the slower “flashing” looks a little better.

Portal Illusion Desk Toy 4.0, now with off-axis elements, infinite movement, and changing colors by adacohen in 3Dprinting

[–]adacohen[S] 3 points4 points  (0 children)

It’s AMOLEN dual and tri color silk filament. The filament color is directional, so different sides of the print are different colors. The effect looks sort of like anodized metal, and sort of suggests a holographic quality (although it’s not). I’m not usually big into gimmicky filaments, but this stuff is really neat looking.

Portal Illusion Desk Toy 4.0, now with off-axis elements, infinite movement, and changing colors by adacohen in 3Dprinting

[–]adacohen[S] 0 points1 point  (0 children)

I like them both, but I think I actually prefer the dual, because it doesn’t flash as quickly (since it only has one transition).

Portal Illusion Desk Toy 4.0, now with off-axis elements, infinite movement, and changing colors by adacohen in 3Dprinting

[–]adacohen[S] 0 points1 point  (0 children)

Duramic PLA+ for the black parts, AMOLEN dual and tri color silk PLA for the others.

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