Hello and welcome back to Switch and Lever!
I'm sure I am not alone in having some precious objects around me which I wish I had more
of.
If only there was a way to copy physical objects in a similar way to sticking it into a copy
machine and hitting print.
Surprisingly, it may not be terribly much more complicated than that.
In this video we will go through the steps involved with scanning a physical object all
the way through holding the copy of it in our hands.
So come on, let's get going!
Comparing copying something flat, like a photo, through a regular copy machine and copying
a physical object is fairly similar.
You first have to scan the object you wish to copy, and secondly you need to print it
out.
First step is scanning.
Various technologies to do 3D scanning have been around for quite some time, but unfortunately
most technologies for highly accurate 3d scanning are very expensive, and require highly specialized
tools.
I have used a couple of these methods in the past when scanning my own head, something
which I used to CNC mill my own coin in a previous video on this channel, as well as
done other fun stuff with.
Fortunately for us there have been great advances made in methods which require no specialized
equipment beyond a decent camera.
In this video I will focus on copying two objects, one small, a ring, and one larger,
a mannequin head, each with their own challenges.
The first, and coincidentally free method, as long as you have a camera, is photogrammetry.
Photogrammetry is the technology of constructing 3D geometry from photographs.
We'll use software to analyze photos of our object to be copied, and the software will
measure and match photos with each other until it hopefully understands how the 3D geometry
of our object fits together.
I say hopefully, because it is dependant on having good photos of your object, from every
conceivable angle.
You really want to make sure you're capturing every little nook and cranny, especially so
if your object is intricate.
A rule of thumb is to try to photograph every point of the object from at least three different
angles, to give the software a good chance of triangulating different points on your
object and successfully constructing 3D geometry.
Photogrammetry works great on slightly bigger objects, like this mannequin head, but can
be used on a much larger scale as well.
When you're taking your photos there are some important things to consider though.
Some tips while taking photos of your object Work in good even lighting
Shoot with small aperture (for crisper photos) Make sure your photos are in focus
Avoid reflective objects (as reflections will vary depending on your angle)
Avoid shadowing your object (as that can cause issues with matching photos together)
Once we have our photos, what do we actually do with them?
I mentioned software just a short while ago, and there are a few really good photogrammetry
packages out there.
The most popular one is probably Agisoft PhotoScan, and if you're curious about it they do offer
a 30 day trial, but after that will charge quite an exorbitant amount of money for continued
use.
Autodesk also offers a software called Recap which also has a free trial, and uses cloud
based analysis, but after the trial comes with a monthly subscription cost.
I started the process of scanning with Autodesk ReCap, but soon moved over to a more recent
addition to the photogrammetry scene called 3DF Zephyr.
Luckily enough they offer a completely free version of their software, and it is truly
amazing!
The free version does have some limitations, like the amount of photos per project is limited
to 50, but for most simpler objects that's going to be more than enough.
If you're interested in diving deeper into different photogrammetry software look at
the Wikipedia article linked in the description, as the selection of software is vast.
The mannequin head that I scanned took quite a few tries to get right, for many reasons.
It's actually easier for the software to scan something that's not completely smooth, something
with more defining features, than what this head was.
The more detail or texture there is the more unique points the software will find.
The plastic of the head was also a bit too reflective to get a good result.
I tried different ways of rectifying that, such as painting the head with a matte primer
and adding sticky dots to give more defining features.
Even though the results were better it still had a lot of issues.
I tried rotating the head on a lazy suzan instead of moving the camera, and tried to
mask the background completely away.
Even though my results left something to be desired, masking is a method which is proven
to work.
Check out Niels Provos' recent video on copying an antique axe head where he successfully
uses this method.
The full video is linked in the description.
Another method to use is to set up an array of cameras around the object, and trigger
them all at once.
This is especially useful with objects which won't stand perfectly still, but on the downside
requires a lot of cameras.
This is being used right now in 3D photobooths, to which you can go, get scanned and have
a miniature copy of yourself made.
Continuing with the head, I even ended up drawing small dots all over, and when that
failed tried connecting them with lines, to create enough points for matching.
Even though quality mostly continued to improve they still were spectacular failures.
In some ways the failures are more interesting than the final result, and you could definitely
use these failed scans for artistic purposes if you were so inclined.
What did end up working was spattering the whole head with both white and black spray
paint, to give a random painted texture over the head.
The results also started getting a lot better once I switched over to using 3DF Zephyr.
It's not immediately visible right here, but up close the detail is quite a lot higher
with 3DF Zephyr compared to Autodesk ReCap.
The mesh is more than ten times more dense.
The results after this process was simply better than I expected going into this!
3DF Zephyr has a fairly easy learning curve.
You drop your photos into the software, and let it match the photos to each other and
calculate what is called a sparse point cloud, which is basically matched points between
the photos.
From this sparse point cloud it will further calculate a dense point cloud, and finally
from this point cloud will create a 3D mesh with your geometry, even with textures if
you so desire.
Prepare to let your computer do quite a lot of heavy lifting, so go and make a coffee
and read a good book while it's computing all the 3D data.
I'm not going into all the little details of how to use the program, but a healthy dose
of experimenting ought to set you on the right path.
If everything went well your geometry should be pretty close to your object.
It's quite likely that the result has some issues though, like holes in the geometry,
or things being completely distorted, sometimes with hilarious results.
For some things, like smaller holes, 3DF Zephyr has tools to fix, for others there's no choice
but going back and taking better photos or spending a lot of time in a 3D modeling software.
In fact, when you're starting out you're probably going to find yourself going back and redoing
the photography several times until you get a result you're happy with and start developing
a method you know works for you and with your equipment.
This is of course not the only thing you can scan using this method, any object that's
roughly the size of a fist and bigger ought to work great, provided you can get around
the object and take photos from multiple angles.
This method has been used extensively to capture architectural features, like this entryway
to where I used to work.
Or this stone step, with every little detail caught.
You don't even need an amazing camera to capture decent results, like this rock nearby where
I used to live, which was put together from just ten photos taken with an iPhone, in just
a few seconds.
Or this face which came from a facade in Stockholm's old city was also captured with an iPhone
camera.
If you have access to a remote controlled helicopter you could even do video shoots
of your house from different angles and use the same software to piece it together into
a model of your house.
This house model came from a website called Sketchfab which has a lot of 3d photogrammetry
models available for download from their users.
I highly recommend to check it out, just follow the link in the description of this video.
Once you start seeing the world with 3D scanning eyes you start to realize that the sky is
the limit, and almost anything can be 3D scanned, whether it should be 3D scanned or not.
And with that, I bring you, bread!
Why would you scan bread?
Why wouldn't you scan bread?
The whole reason I actually started this project was because I wanted to copy a very special
object, a plastic ring I've had since I was a kid.
I think I got this (and a few like it) from a chewing gum machine well over 25 years ago.
I loved this ring, but it's made of plastic and my fingers just aren't the size they were
when I was a kid.
To make a long story short, I wanted to copy this, so I once again could wear my childhood
ring.
I tried, repeatedly, to use photogrammetry to get this ring scanned.
The reflective surface obviously wouldn't work, but neither did painting it with a gray
primer, and neither did giving it a little structure.
It was time to turn to another method.
Another very popular method of scanning is structured light scanning, where you usually
pass a laser line over an object and use a camera to interpret how that line bends over
the object.
There are more budget variants to use this, even some homebrew hacks where you can build
your own scanner.
At my previous place of employment I was lucky enough to find an old NextEngine 3D scanner
hidden away in a dusty corner and managed to get it up and running again.
This has a few years on it, and newer ones produce a bit better results, mainly due to
better cameras, but this was sufficient for what I needed.
It constructs a point cloud, similarly to what 3DF Zephyr does from photos.
The strength is that you can easily scan once, reposition the item being scanned and scan
again, to get all angles of your item.
Then you can merge all of these in the software.
Bear in mind that this method still has the same limitations as before when it comes to
reflective surfaces, so priming or dusting the object with talcum powder may be a good
idea.
NextEngine's 3D scanner is just one such scanner on the market, and it does cost a pretty penny.
However, if you need really high quality meshes using structured light scanning technology
may be the only way to go.
There's a good comparison of different methods on the NextEngine website, which shows what
you can expect from each method.
Unfortunately though they don't really compare it to better photogrammetry methods, like
Agisoft Photoscan, or 3DF Zephyr.
Also, the open source community is working on exciting things in this field, like the
FreeLSS platform, which is essentially an open source, 3D printed, laser line scanner,
based on Raspberry Pi.
All the material you need is open source, so if you want to experiment with it yourself,
do check it out!
You can actually do proper laser 3D scanning as well, using LIDAR sensors and essentially
measuring the time for the laser to bounce from the emitter and back to your sensor.
It's generally not something that's commonly used for the kind of scanning that we're doing
in this video, but is common when measuring elevation and creating topographical maps.
If you want to experiment at least with the source material from such scans a lot of the
earth is available for download in various Digital Elevation Map formats.
With them you can create 3D topographic maps, to use for visualization or similar things
which we will do later in this video.
Back to the ring, and as you can see the result of the scan was still not perfect, but compared
what I got from doing photogrammetry it was like night and day.
The result from the scanner may seem quite rough, but aside from the holes where the
scanner couldn't reach, it is a pretty accurate representation of the original ring, as the
plastic itself isn't all that high definition and has plenty of small bumps and mold lines.
So, there is still plenty of work to be done.
which is mostly true regardless of 3d scanning method.
The more care you take in the scanning the less issues you have to fix afterwards.
Either way there may be noise in the scan, disjointed parts, holes or other geometries
which need to be fixed.
As you can see the skull ring still has some major issues, but most is there.
Using a software package like Zbrush or Sculptris, which allows you to sculpt 3D geometry rather
than use traditional 3d modeling tools you can fix these geometries and smooth the surfaces.
I cleaned up the ring, smoothed some areas and increased the definition in others, until
the ring looked the way I wanted to.
Sure, it was not an exact representation of the plastic ring I wore as a child, but it
definitely shares provenance.
Right now, regardless of which method you used, still all we have is some 3D geometry
in the computer, but I think you can easily figure out how to get it back into the physical
world.
That's right, through the wonders of 3D printing!
First of all let's tackle the head.
Once I had cleaned it up after the scanning I simply pushed it out in ABS plastic on a
Flashforge Dreamer 3D printer, and indeed it came out pretty nice.
Just copying something may be fun, but you could also do more interesting things with
it.
I did some modeling and reprinted the head, making a snazzy USB flash drive from it.
Stupidly I didn't take into account how thin my computer is, but eh such is life.
If you don't have access to a 3D printer yourself there are services, such as Shapeways, which
happily will print your models for you in a variety of materials.
I've used Shapeways plenty of times in the past, so it's no surprise I'm a fan, but I
have no affiliation with them and my endorsement is entirely from my own experience.
In a previous video, making a branding iron, I demoed how you can 3d print steel with Shapeways,
but since we're making a ring something a bit more sparkly is definitely more aprorpriate.
This time around we're printing in silver.
Well, that's kind of a misuse of the term.
Shapeways will actually print it in wax, and then use the wax to cast a silver piece for
you.
The process may not be the cheapest, but it's an entirely custom part, and for that it's
not terribly expensive.
Try going to a jeweler and getting a custom piece like this made and see what it will
cost.
Quite frankly, I couldn't be happier.
The ring fits and feels amazing, and while it arrived to my doorstep highly polished
and reflective given a couple of months of use it's tarnished beautifully, and got an
amazing depth to it.
I know wearing a skull ring may be seen as tacky by some, but hey, live and let live
huh?
Of course, you can choose to print things out in other metals, or plastics, even colored
or transparent plastic if that catches your fancy more.
Remember the scanned bread from before?
Yep, you could even have a piece of 3d printed bread, though I wouldn't recommend eating
it, even though it is gluten free.
I will actually be giving away this 3d print to one lucky instagram follower, so be sure
to head on over to the Switch & Lever instagram account for more information and rules for
the giveaway.
Come on, you know you want this absolutely unique piece of Switch & Lever memorabilia!
That's really all there is to it, if you have a camera you can start experimenting with
photogrammetry today already.
Download 3DF Zephyr, photograph your favourite thing, sleeping person, an unsuspecting pet,
your house, or whatever else floats your boat, and print and scatter copies of the weirdest
things imaginable all around.
Thank you so much for watching, I really hope you enjoyed this much longer than usual video,
and maybe also learned a thing or two.
Even so, there are plenty of other videos on this channel, why don't you give one or
thirty eight of them a look?
Remember to head on over to instagram and enter the raffle for the 3d printed bread.
You could be the lucky winner!
Until next time!
No comments:
Post a Comment