Get Great 3D Scans With Open Photogrammetry

April 7, 2019 by Elliot Williams 24 Comments

Not long ago, photogrammetry — the process of stitching multiple photographs taken from different angles into a 3D whole — was hard stuff. Nowadays, it’s easy. [Mikolas Zuza] over at Prusa Printers, has a guide showing off cutting edge open-source software that’s not only more powerful, but also easier to use. They’ve also produced a video, which we’ve embedded below.

Basically, this is a guide to using Meshroom, which is based on the AliceVision photogrammetry framework. AliceVision is a research platform, so it’s got tremendous capability but doesn’t necessarily focus on the user experience. Enter Meshroom, which makes that power accessible.

Meshroom does all sorts of cool tricks, like showing you how the 3D reconstruction looks as you add more images to the dataset, so that you’ll know where to take the next photo to fill in incomplete patches. It can also reconstruct from video, say if you just walked around the object with a camera running.

The final render is computationally intensive, but AliceVision makes good use of a CUDA on Nvidia graphics cards, so you can cut your overnight renders down to a few hours if you’ve got the right hardware. But even if you have to wait for the results, they’re truly impressive. And best of all, you can get started building up your 3D model library using nothing more than that phone in your pocket.

If you want to know how to use the models that come out of photogrammetry, check out [Eric Strebel]’s video. And if all of this high-tech software foolery is too much for you, try a milk-based 3D scanner.

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Recreating Classic Model Kits With Modern Tech

April 5, 2019 by Tom Nardi 17 Comments

It used to be that if you wanted to make a nice scale model of an airplane, you’d be building the frame out of thin balsa ribs and covering it all up with tissue paper. Which incidentally was more or less how they built most real airplanes prior to the 1930s, so it wasn’t completely unreasonable to do the same on a smaller scale. But once injection molded plastics caught on, wood and tissue model kits largely went the way of the dodo.

[Marius Taciuc] wanted to share that classic model building experience with his son, but rather than trying to hunt down balsa kits in 2019, he decided to recreate the concept with modern techniques. His model of the Supermarine Spitfire, the vanguard of the British RAF during the Second World War, recreates the look of those early model kits but substitutes 3D printed or laser cut components for the fragile balsa strips of yore. The materials might be high-tech, but as evidenced by the video after the break, building the thing is still just as time consuming as ever.

Using a laser cutter to produce the parts would be the fastest method to get your own kit put together (you could even cut the parts out of balsa in that case), but you’ll still need a 3D printer for some components such as the propeller and cowling. On the other hand, if you 3D print all the parts like [Marius] did, you can use a soldering iron to quickly and securely “weld” everything together. For anyone who might be wondering, despite the size of the final plane, all of the individual components have been sized so everything is printable on a fairly standard 200 x 200 mm print bed.

While there’s no question the finished product looks beautiful, some might be wondering if it’s really worth the considerable effort and time necessary to produce and assemble the dizzying number of components required. To that end, [Marius] says it’s more of a learning experience than anything. Sure he could have bought a simplified plastic Spitfire model and assembled it with his son in an afternoon, but would they have really learned anything about its real-world counterpart? By assembling the plane piece by piece, it gives them a chance to really examine the nuances of this legendary aircraft.

We don’t often see much from the modeling world here on Hackaday, but not for lack of interest. We’ve always been in awe of the lengths modelers will go to get that perfect scale look, from the incredible technology packed into tiny fighter planes to large scale reproductions of iconic engines. If you’ve got some awesome model making tips that you think the Hackaday readership might be interested in, don’t be shy.

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CNC Your Own PCBs With A 3D Printed Mill

April 5, 2019 by Brian Benchoff 31 Comments

Yes, you can whip up a design for a printed circuit board, send it out to one of the many fab houses, and receive a finished, completed board in a week or two. There are quick-turn assembly houses that will manufacture a circuit board and populate it for you. But sometimes you need a board now, and that’s when we get into home PCB fabrication. You can do this with either etching or milling, but [Renzo] has a great solution. He built a 3D printed milling machine that will make a printed circuit board.

The design of this tiny micro mill is based on a handheld rotary tool, also called a Dremel, but that’s like Kleenex, so just buy a Proxxon. This mill is designed with 3D printed T-track and constructed with linear bearings on smooth rods with standard NEMA 17 stepper motors and herringbone gears for little to no backlash. There is quite a bit going on here, but lucky for us [Renzo] has a video tutorial of the entire build process available for viewing below.

We’ve previously seen some of [Renzo]’s previous efforts in homemade PCB fabrication, up to and including applying green soldermask with the help of Fritzing. This is good, very good, and the only thing that really separates this from manufactured PCBs is the lack of plated through holes. That’s just a bit of graphite and electroplating away, and we’re looking forward to [Renzo]’s further adventures in making PCBs at home.

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Print Your Own Large Format Camera

April 4, 2019 by Brian Benchoff 32 Comments

Just like how vinyl records are seeing a resurgence in an era of digital streaming music, we’re also seeing a lot of people interested in another technology that is as obsolete as it is perfected. The large format camera is back as a kit, it makes huge images, and there’s an Open Source version if you want to print your own.

The Standard 4×5 is a project to build an affordable, lightweight, 3D printed large format camera. It was a Kickstarter project last year, and after a lot of work the project has now been improved with better rails, better bellows, and a lot of refinements.

As an Open Source project, this camera has all the models available, dimensioned drawings for all the metal parts, and a lot of patience required to make your own bellows. With this, you can screw a lens on take a picture, just make sure you get the focus right with some ground glass beforehand.

As for why anyone would want a large format camera, there are a few things that big cameras with tiny apertures can do that nothing else can. Here’s the pinhole solution for the Standard 4×5 with a laser drilled hole, and with this camera you’re getting an f-stop between f/240 and f/520.

Now Toto’s Africa Is Stuck In Our Heads

April 1, 2019 by Brian Benchoff 24 Comments

April Fool’s Day is bad. April Fool’s Day is a terrible, horrible, no good, very bad day. For one day a year, we’re inundated with pieces that can, accurately and without any sense of irony, be called fake news. YouTube is worse. But you know what’s worse than April Fool’s Day? A hundred children playing plastic recorders. But it’s April Fool’s Day, and things must get worse. Here’s a vacuum cleaner playing Africa by Toto.

This is the latest build from [James Bruton] or [Ecks Robots Dot Co Dot UK], who is the king of building just about anything with 3D printers. He’s got a BB8 and some of the cooler Star Wars droids, a Hulkbuster, and openDog. When it comes to confabulating robotics and 3D printers, [James] is the king. But this is April Fool’s Day, and if you’re a big YouTuber, you need to do something annoying. [James] is the king.

This build uses a Henry vacuum cleaner, a canister vacuum with a silk screened face, because why not, and you’re not truly living until you put googly eyes on your Roomba. Also, all vacuums in England are Hoovers, because reasons. In collaboration with [Mothcub], [James] adapted cheap children’s plastic recorders to a Henry vacuum cleaner with a few 3D printed parts, some servo-controlled valves, and a bit of plastic tubing. While using cheap kid’s recorders as the tone generator in what is effectively a pipe organ is interesting (the stickers over the holes are a great idea), this is something that should not be done ever. This idea should not be replicated. These recorders are not in tune and I don’t know how because they’re just one piece of plastic that came out of the same mold.

The servos, and therefore the entire pipe organ, are controlled via MIDI, which makes this the first DIY MIDI pipe organ we’ve seen. It’s a proof of concept, and a pretty good one. It also sounds terrible. This is proof that cheap plastic recorders don’t sound good. The video is below, and I highly suggest skipping the second half.

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Finding Plastic Spaghetti With Machine Learning

March 29, 2019 by Tom Nardi 10 Comments

Among 3D printer owners, “spaghetti” is the common term for the tangled mess of stringy plastic that’s often the result of a failed print. Fear of their print bed turning into a hot plate of PLA spaghetti is enough to keep many users from leaving their machines operating overnight or while they’re out of the house. Accordingly, we’ve seen a number of methods that allow the human operator to watch their print remotely to make sure everything is progressing smoothly.

But unless you plan on keeping your eyes on your phone the entire time you’re out of the house, there’s still a chance some PETG pasta might sneak its way out. Enter the Spaghetti Detective, an open source project that lets machine learning take over when you can’t sit watching the printer all day. Their system plugs into Octoprint to monitor your print in real-time and pause it if it starts looking particularly stringy. The concept is still under development, but judging by the gallery of results submitted by users, the system seems to have a knack for identifying non-edible noodles.

Once the software comes out of beta it looks like the team is going to try to monetize it by providing hosting and monitoring services for a monthly fee, but as it’s an open source project, you’re also able to run the software on your own machine. Though the documentation notes that the lowly Raspberry Pi doesn’t have quite what it takes to handle the image recognition routines, so you’ll need a proper computer if you want to self-host the service. Could be a good use for that old laptop you’ve got kicking around the lab.

As demonstrated in the video after the break, the system’s “spaghetti confidence” is shown with a simple to understand gauge: green is a good-looking print, and red means the detective is getting a sniff of the stringy stuff. If your print dips into the red too much, Octoprint is commanded to pause the print. The user can then look at the last image from the printer and decide to either cancel the print entirely, or resume if the Spaghetti Detective got a little overzealous.

Frankly, it’s a brilliant idea and we’re very interested to see where it goes from here. Assuming you’ve got Octoprint controlling your 3D printer there are some very clever monitoring systems out there currently, but since spaghetti isn’t the only thing a rogue 3D printer can cook up, having an extra line of defense sounds like a good idea to us.

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Casting Car Emblems Via 3D Printing

March 28, 2019 by Lewin Day 10 Comments

Casting is a process that can be quite demanding for the first timer, but highly rewarding once the basic techniques are mastered. It then becomes possible to quickly and reliably produce metal parts en masse, and with impressive tolerances if the right method is chosen. [VegOilGuy] has been experimenting with lost PLA casting, and decided to see if it could be applied to car emblems.

The process begins with 3D models of various car emblems, primarily sourced from Thingiverse. These are printed in PLA, with sprues added to assist with the casting process. The parts are sanded to avoid unsightly print lines on the finished product, and any voids filled with wax. The various emblems are then assembled onto a casting tree, with extra sprues added to improve metal flow with wax and further PLA parts.

The investment mold is then created with plaster, and baked to remove water and melt out the PLA. This is crucial, as any water left in the mold can react explosively with the molten aluminium bronze. The mold is then filled with metal and then allowed to cool. The plaster mold is destroyed, and the parts can then be removed. Final processing involves a trip through a rock tumbler before final polish with sandpaper.

[VegOilGuy] gets impressive results, with the parts looking excellent in their bronze colour. This is an unconventional color for a car emblem, but it’s noted that this material is an excellent candidate for chrome plating to get a more OEM finish.

You might find your lost PLA casting experiments could benefit from the help of a microwave, too. Video after the break.

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