3d printing – Terence Eden’s Blog

3D Printing My Teeth

@edent — Fri, 21 Jun 2024 11:34:17 +0000

As previously mentioned, I recently had a some dental issues and learned how to view a CT Scan in 3D using Linux.

At a hackathon last week, my friend Sidd brought along a 3D printer. How hard is it to convert a CT scan to a file suitable for printing? Slightly trickier than I expected! Most of the guides I found were outdated, or the software didn't work on Linux, or the instructions assumed a level of expertise that I just didn't possess.

So here's my simple guide to getting it working.

I used InVesalius 3 - specifically, the FlatPak version.

I opened the folder of .dcm files and loaded the record it found. From there, you can adjust the sensitivity of the mask.

That shows the 3D version which you can interact with. Then the surface can be adjusted - for example to select the largest area, or other attributes.

Finally, the data can be exported to STL.

Once exported, I opened it in Meshlab to view it.

You'll notice that there are still a few weird lumps in there. Ideally I'd find a decent 3D editor to smooth them out.

The Print

Sidd handled this for me. Rather than spending several hours printing a full-size model, we opted for a scaled down version which would print in about 45 minutes.

After removing all the support material - it looked pretty cute!

Close up, maybe less so 😂

ToDo

The resolution of a CT Scan isn't massive - 500x500px. So there will always be a limitation to the details it can pick out - and errors will creep in.

I don't have the skills to edit the file - but I suppose I can learn.

But, yeah, it's perfectly possible to convert CT Scans into physical objects.

Où est L'Inconnue de la Seine en 3D?

@edent — Mon, 13 Sep 2021 11:43:20 +0000

Twitter can be amazing sometimes...

I was reading about "L'Inconnue de la Seine". The face of a young woman found drowned in the river Seine in the 1800s. Her death mask was enormously popular - with copies of it appearing all over the world. Her smile was compared to the Mona Lisa and her face decorated the popular salons of the day.

Her death mask was even the basis for the first "CPR Doll". Her death has helped save more lives than anyone can possibly count.

There are thousands of photos and drawings of the mask - but no 3D scans.

Twitter, being a ~~wretched hive of scum and villainy~~ machine for serendipity, soon found me someone who works somewhere that makes 3D scans of busts.

But they didn't have L'Inconnue in their collection.

Luckily, there was a museum nearby which had a copy of her face and, before the day was out, she'd been located!

And promptly scanned!

A few days later, and...

(Try dragging the object with your finger or mouse.)

L'Inconnue de la Seine in 3D

Back in 2013, I asked "Should Wikipedia Have 3D Models of Sculptures?" I speculated on how soon it would be before Pirate Museums of illicit and unauthorised scans appeared.

A modern mobile phone and a few minutes in a room with good lighting is all⁰ you need and - WHAM - you've got a 3D model.

Huge thanks to Jonathan Beck for the scanthe.world project.

OK, you need some decent software and the skills to tidy up the model. ↩︎

Episode 27 - Hannah Cameron's makerspace adventures

@edent — Wed, 19 Jun 2019 06:51:09 +0000

Hannah works for Eagle Labs, where she 3D prints things and builds IoT lamps.

🔊

💾 Download this audio file.

3D Printed, Arduino Powered, Educational, Open Source, Micro-Robots!

@edent — Wed, 17 Feb 2016 12:01:23 +0000

Last week I was invited to attend a product launch by BQ. They're a small company based out of Spain who create some curiously innovative products - including smartphones which natively run Cyanogen. I'm particularly looking forward to reviewing their Ubuntu Tablet later in the year.

The thing which really caught my eye was Zowi (pronounced Zoë).

It looks like this: And it dances like this:

https://shkspr.mobi/blog/wp-content/uploads/2016/02/zowi.mp4

Ok, but what is it?

Here's what you need to know. It's an Arduino powered robot which you can control via BlueTooth. It's full extensible and IT COMES WITH AN ALLEN KEY!

This "toy" is designed to be taken apart, remixed, and reassembled. Undo two screws and get right inside its guts.

GPIO pins, LED display board, ultrasound sensors, motors, external buttons, and a micro-USB socket.

Oh, what's that? You don't like the two-legged style? OK - 3D print your own body for it, like this:

They have very active GitHub repositories which also include the 3D designs if you want to print your own Zowi.

At the demo they had a Scratch-like programming interface running on their Android tablets. Program the robot and play games with it, all from your phone. No PC needed.

My favourite part? "This robot is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License."

The Zowi will be £80 on launch and I can't wait to get my hands on one.

3D Printed Letter Press

@edent — Fri, 11 Apr 2014 14:49:18 +0000

Rewired State have just announced "End Of The World Hack"

We know the earth is about to be bombarded with solar flares and magnetic storms of varying ferocity on July 4th, 5th and 6th 2014, by which time the infrastructure of the energy and communications networks will have been completely decimated across the entire planet.
You have 48 hours to best prepare the human race for survival, through the chaos, and on to a successful future. After which time there will be no electricity and no electronic technologies available.

That's such a cool idea for a hackathon! It got me thinking what I would do in that situation.

Well, obviously, printing out survival manuals and important parts of Wikipedia would be a good way to prep. Ok, but what do you do when that printed copy gets damaged or destroyed? How do you print out another one?

LET'S BUILD A PRINTING PRESS!

I have the square-root of naff-all experience in building a letter press, so I thought I'd do some experiments before attending the hackday and making an idiot of myself :-)

Firstly, I created a spreadsheet containing capital letters, numbers, and punctuation. No chance of Unicode - this barely covers ASCII!

The end result looks something like this:

The font is OCR-A - so that future computers can read our printed documents more easily.

The thick black borders give us nice separation when printing out.

Finally, the image is flipped horizontally.

I used png23d to convert the image into an .STL file

png23d -v -f surface -t 0 -l 32 -w 100 -d 5 -O 1 -o stl Letters.png Letters.stl

That ensures the black is "don't print", the white is the highest physical print point, and the greys are proportional in between.

After a few failed attempts, things started to take shape...

Leading to this lovely collection of letters:

As you can see - a few of them moved during printing, so it might be an idea to print it as a single bed and then snap the letters out.

You can download the .STL file from Thingiverse.

To Do

I'm not usually a fan of massive preparation before a hackday - but given the time involved in printing out these test pieces (3 hours including warm-up / down) I thought it prudent to experiment.

Still to do at the actual event (and do come along to help!)

Build scaffolds / trays for the letters to fit into.
Create ink. (Blueberries? Beetroot? Soot? How?!)
Actually put ink on the letters, then paper, then see if it works :-)
Work out how many of each letter is needed.
How small / large should they be to cover a sheet of A6?
Which fonts look best?
Are they durable enough? How much physical impact can they take?
Would it be better to create individual stamps rather than sets of letters?

Lots of work to do! Hope to see many of you at End Of The World Hack on 4 - 6 July 2014.

3D Printing at Over The Air

@edent — Wed, 02 Oct 2013 15:44:53 +0000

This is a necropost - resurrected from the now defunct blog of a previous employer.

We had an amazing time at Over The Air 2013. We’ve teamed up with ThingMaker to digitally scan attendees. Our long term aim is to release on GitHub a collection of faces which artists and game designers can re-use.

The definite highlight was scanning Annie, one of the veterans of Bletchley Park.

Our thanks also to Faberdashery who were able to supply us with filament for the 3D printer in exactly the right shade of blue for our logo.
I’m really looking forward to getting my hands on some of their glow-in-the-dark material.

Here are some of the great photos taken by us and our new friends. Special thanks to Rachel Clarke and Simon Kisner

3D Printing the 2600 Whistle

@edent — Sat, 28 Sep 2013 20:19:17 +0000

Perhaps the most legendary piece of plastic in the hacker community is the humble "Cap'n Crunch" whistle. The free-in-cereal whistle was able to emit a piercing shriek at 2600Hz - the exact tone required to unlock the US phone network.

So, because it's all I seem to do these days, I turned my my trusty RepRapPro and decided to see whether it was possible to 3D print a whistle which could produce the same frequency.

I found a customisable whistle on Thingiverse and customised it to include the Over The Air hashtag.

Rather than do any funky customisations with radius or length, I simply scaled the whistle in Slic3r.

I made them at 75%, 85%, 100%, and 100%.

The print wasn't without issues. Because of the large opening, the top layer didn't seal properly - even on the smallest print. The logo printed reasonably well - and the holes in the side were easily sealed with my fingers. But I might adjust the model for a thicker top layer.

The models come with an integrated "pea". The little ball in printed inside the barrel - a hard poke with a sharp stick set the ball free.

So, how did it sound?

🔊 3D printed whistle at #ota13
🎤 The BooBot

💾 Download this audio file.

Not bad! We broke out a tonal analyser on a smartphone and, on the smallest whistle, I managed to just about hit 2600Hz!

The 3D print is rather rough and was quite harsh on the lips - so it's worth sanding the final print down or rubbing some acetone on it before blowing.

Now, obviously, this doesn't look exactly like the original whistle. There are no 3D models I could find - although there are several rather detailed photos.

For my next step I can go one of two ways. Either refine the existing whistle so it reliably produces the 2600Hz tone - or try to make a replica of the bo'sun whistle and then get that pitch perfect. Thoughts?

Oh, and the tone is really loud and annoying for anyone nearby!

Should Wikipedia Have 3D Models of Sculptures?

@edent — Sun, 08 Sep 2013 07:00:29 +0000

I was wandering round The Henry Moore Foundation last Friday - thanks to the delightful wedding of my good friends Mike and Nikki.

Looking at the abstract statues and carvings, I was struck not only by their beauty, but by how easy they would be to reproduce with a 3D printer. Ok - ok! I'm a little obsessed since building a RepRapPro for work - but hear me out.

Wikipedia has been collecting high-resolution scans of famous works of art - although not without controversy - and providing them for free to the public. For example, you can download a 90MB image of the Mona Lisa at 7,479px * 11,146px, detailed enough for just about any purpose.

The controversy with Wikipedia and the National Portrait Gallery was of volunteers downloading ultra-high resolution scans which had been created by the museum and were not originally intended to be set free.

Now we have a situation where many museums are actively laser scanning their artefacts - the Smithsonian have a great 3D collection. It's very easy to grab the Smithsonian's 3D scan of the Willendorf Venus; just check the source code of that page. Some time later, the 3D file can be converted to an STL and shared freely for anyone to view and download.

And, if galleries aren't scanning their own sculptures, what happens when Wikipedia volunteers start taking 3D photos of famous works of art? It wouldn't be the hardest thing in the world to sneak a Kinnect and laptop into a gallery and surreptitiously create a 3D mesh. Or, even, just take lots of photos at different angles and use software to determine the dimensions.

And that's exactly some enterprising chap has done. With nothing more than an iPhone and used the 123D Catch software, it takes less than five minutes to make a 3D model of Moore's "Old Flo".

That 3D file could easily be embedded into Wikipedia in much the same way that high-resolution photographs are today. This would allow visitors to experience an object in 3D in their browser. See, for example, how GitHub manages this.

With an ancient sculpture, I think that's acceptable. The 3D scan is a series of facts about an object. It's a slavish copy of a work of antiquity - no more deserving of copyright than a photocopy of a Shakespeare folio.

But what about Henry Moore? Most of his art was created in the second half of the 20th century, and he died in 1986. In most parts of the world, his copyright persists for at least another 20 years.

I'd love to see interactive 3D models of his work embedded in Wikipedia - but is it legal or moral for people to create such items?

I'm not a copyright expert. I feel uncomfortable that the 3D scan of "Old Flo" has been unilaterally released by the scanner as Creative Commons - Attribution - Share Alike. The scan is undoubtedly its own work - but just as taking a photo of a portrait doesn't necessarily create a new and copyrightable piece of work, I'm not sure that a straight scan of a sculpture somehow releases the object from the bonds of copyright.

Today, we are exactly where we were with MP3s in 1998. Converting art to .stl files is a niche sport for dedicated fans, it requires expensive hardware to reproduce the original art, and the quality isn't that great.

15 years later and our laws have barely caught up with the fact that people can reproduce movies and music in nano-seconds.

How will our copyright laws react when high quality models of sculptures are freely shared on underground art exchanges?

3D Printing A Fossil

@edent — Sat, 31 Aug 2013 08:00:32 +0000

Earlier this week I tried my hand at printing fossils. The print didn't perfectly, but it was quite encouraging.

Museum Victoria - an Australian institution - has released a 3D scanned trilobite on Thingiverse.

I trimmed the model - to make the bed shallower and the sides neater - and hit print. I'm pretty impressed with the results:

My remixed model is also available on Thingiverse if you'd like to have a go at printing your very own fossil.

I'm impressed with the fidelity of the print. It came out much better than I expected. You can really see a lot of the detail. I think it could be an excellent way to introduce people to fossils, to really give them a chance to examin them and feel them - even if they can't get to a museum.

3D Printing Fossils

@edent — Tue, 27 Aug 2013 14:26:27 +0000

I've just discovered the amazing 3D Fossils site of the British Geological Survey.

The GB3D Type Fossils Online project, funded by JISC, aims to develop a single database of the type specimens, held in British collections, of macrofossil species and subspecies found in the UK, including links to photographs (including 'anaglyph' stereo pairs) and a selection of 3D digital models.

What that means is that they have thousands of British fossils available as freely downloadable 3D models! Even better, all the models are Creative Commons (Attribution-NonCommercial-ShareAlike 3).

So, I decided to experiment with printing out a Fossil on the 3D Printer I built for my employer.

I chose a model more-or-less at random - an Ammonite from Dorset.

I used netFabb for Linux to slice the model along the Z-Axis. This ensured it had a smooth, flat foundation.

The resolution of this particular scan was quite low - and is taken from a plaster cast of the original small fossil - but even still, I'm impressed with how well the print turned out.

The printer got a little skew-whiff towards the end of the print, so I finished it early. Even so - it's easy to see how well some of the features have printed out.

Now I need to find some larger, and more interesting things to extrude!

3D Printed Coins

@edent — Mon, 05 Aug 2013 07:30:19 +0000

It goes without saying that counterfeiting coins is illegal. Sir Isaac Newton when he was Master of the Mint, had people hanged or tortured for illegally producing coins. So, don't do it, ok!

That said, coins are very useful as calibrators for 3D printers. They come in various shapes, sizes, and thickness. More importantly, it's really easy to compare a 3D printed coin with one in your pocket. Or, even, just by looking at them.

I've spent the last few days creating a basic set of 3D coins - based on the UK's currency.

The Royal Mint maintains openly available specifications for all UK coins. Predictably, they don't have the coins in a readily available 3D format :-)

The faces and designs of the coins are also not available. Using a high resolution photo of the designs could be used to generate a height map suitable for printing - but I'll leave that for version 2!

One interesting thing to note, the 20p and 50p are not heptagons and pentagons as many people think. They are Reuleaux Polygons. The mathematics behind them is a little to taxing for a hungover Sunday morning, so I used Dan Newman's freely available OpenSCAD template from Thingiverse.

You can download the UK coins STL file from Thingiverse or fork the coins on GitHub. Hopefully, in the next week or so I'll print them out on the new 3D printer I've been building.