2. Digital bodies#
This week we worked with 3D models of bodies, learned about 3D scanning and unwrapping 3D models into 2D, and made mannequins out of laser cut cardboard.
What I made#
My mannequin was made from laser cut cardboard pieces, assembled with various kinds of thread, rope, and a bit of masking tape for structural help. In all honesty it was a pain to assemble and I wouldn’t be in a rush to do it again, but because there were so many fiddly parts to it, I learned a lot! If you look closely you can see some flaws, and there are a few pieces missing at the back, because I decided that it would be better to have some of the mannequin’s pieces missing than to be missing my sanity.
At the end of this page there’s a list of links to the different software tools that were used to make this.
Step 1: Making models of bodies with Makehuman#
To make a mannequin, you need a model of a body! You can download an existing model from various places online, use 3D scanning to make a model of a real life human, or use software such as Makehuman, which generates customisable models of humans.
On opening, Makehuman generates an ‘average’ human, which you can see in the screenshot below. In the ‘modelling’ tab, you’ll see different tabs for all the areas of the body - you can reshape and resize almost everything you can imagine. If you want to enter custom measurements, the ‘measure’ tab will allow you to put in precise measurements. This can be super handy if you want to make a realistic model of a real human, where 3D scanning is difficult (for example if the person you are modelling has physical issues which make standing in the right position for 3D modelling difficult).
It’s important to note that with some body parts, changing one side of the body will automatically make the same change to the other side of the body, but other times, it won’t.
I decided to make an unusual looking human with a small head, long limbs, and a broad torso. There are many other things you can do with Makehuman, such as adding clothing, posing your human in different positions, and so on, but to make a mannequin, we don’t need these. Export your file to .obj format, and you’re done!
Step 2: Getting rid of body parts you don’t need with Meshmixer#
Makehuman doesn’t allow you to slice up your 3D model, so to isolate just the torso to make a mannequin, we need another tool. There are lots of ways to do this, such as using 3D design tools like Fusion or Rhino, but as a person who has zero experience in 3D design, I went with Meshmixer for Fusion 360, because it was easy to get started, and I only needed to invest a little bit of time in getting it to do what I needed.
Start by importing the .obj file you exported from Makehuman. You should see something like this (mine has intense blue eyebrows because I added eyebrows in Makehuman for no particular reason).
To remove parts of the mesh, click on Edit in the left hand menu, and select Plane Cut. Then just click and drag the arrows to move the location of the cut in the x/y/z directions. to change the angle, click on the semi-circle and drag it to change the angle of the cut.
I made a second plane cut to remove the head, and a third one to remove one of the arms. Then I clicked Edit and Mirror to remove the second arm.
Then go to File, and Export, and export in .obj format again.
Step 3: Turning a 3D model into 2D shapes with Slicer#
At TextileLab Amsterdam we made our mannequins out of cardboard, using the laser cutter. As laser cutters can only cut 2D shapes out of flat material, this means we need to slice our 3D model into a number of 2D shapes, so those can be laser cut and assembled into a 3D mannequin. I used Slicer for Fusion 360 to do this.
First, import your model - the .obj file you exported from Meshmixer, into Slicer. Then change the Manufacturing settings (top left of the screen) and enter the size of the material you’ll be using. This makes sure that the plans Slicer generates will be the right size for your material - we were using 110cm x 90cm cardboard, with 3mm thickness, so I entered those numbers in the menu at the bottom of the screen. Make sure to also check that your object size is correct! In the menu on the left hand side you can see your model’s dimensions, and the units they’re measured in.
Next, Slicer has several different options for how to unpack your 3D shape into 2D slices. I decided to go with the folded panels option, which turns your 3D model into a collection of triangles, which can be cut on the laser cutter and then assembled back into a 3D shape.
You can adjust the detail of your model by changing the number of vertices (aka joins between panels) - more vertices = more detail, but more work to assemble. Less vertices means less detail, but less assembly work, so I settled on 55 vertices, which was the lowest number possible where the object still looked vaguely mannequin-shaped.
You also need to choose a way to connect your panels: in the left-hand menu there is a drop-down list of different ‘joint types’ - tabs, rivets, holes for lacing, etc - different ways to make the panels slot together, or make holes in them. I chose the Laced option, which created holes for sewing. I noticed straight away that the holes seemed really close to the edges of the panels. Thankfully you can adjust the size of the holes, the distance between them, and the distance from the edge, by clicking the pencil icon next to the drop-down menu with the joint types.
On the right hand side of your screen, you might see some panels highlighted in red. This can mean that the panel is too large for your material, or that there’s a problem with the joints - e.g. some of your panels are too small to insert lacing holes into. You can play around with the different settings (number of panels, joint size and spacing) to try and get a configuration with no errors. There’s also an add/remove seams function, which is supposed to allow you to merge panels, or split them into smaller ones. But I didn’t have much success getting this to work ¯_(ツ)_/¯
When you’re happy with how everything looks, click on Get Plans, and export as a .dxf file (you can also export to pdf if you want to import the plans into another software for further editing).
Word to the wise: save your file! Even after you’ve exported the plans, it’s useful to be able to look at your model to see how everything fits together. If your laptop crashes, like mine did, you’ll find out that if you open Slicer again and put in the same settings, the numbering of the panels ends up different…this is a massive pain when it comes to assembling your mannequin Ծ_Ծ
Step 4: Testing#
Before laser cutting, I wanted to figure out what would be the best size, spacing, and distance from the edges, for the lacing holes. I tested three different configurations by exporting three sets of plans, importing them into Adobe Illustrator, and making a new file with two pieces from each settings variation. I then cut these on the laser cutter, tested them with different kinds of cord / string, and went with a hole radius of 4mm, and a spacing / distance from the edge of 15mm.
What I’ve since learned is that the spacing of the holes can get a bit messed up on smaller pieces, so in the testing phase it’s a good idea to try cutting both smaller and larger pieces.
As you can see in the right image above, Slicer numbers each panel for you. There’s a big number on each panel (usually, but not always, in the middle) which tells you the number of the panel itself (let’s call this the panel number). And there are three small numbers on each of the three triangle edges, which tell you which panel to connect each edge to (we’ll call these the edge numbers).
Now, the problem is that there’s a bug in the numbering. The edge numbering starts counting from 0, while the panel numbering starts counting from 1. Have a look at the image below. The panel on the right is panel no. 2, and the edge on the left side is numbered 62. You’d think this means you need to go and find panel 62 and attach it there, but because of the numbering bug, you actually need to go and find panel 63, as I’ve done. Fun times!
Are you confused? I was too! It took a fair amount of googling and staring at the panels to figure out how it was supposed to work. I found a thread in the Autodesk support forums from May 2018 where people were complaining about this, so apparently it’s not a new problem! Once you understand what the bug is, it’s easy enough to work around it, but it slows down the assembly because you’re constantly thinking about whether you’ve got the numbering right.
Step 5: Laser cutting#
How your laser cutter is used will vary depending on the brand and model you’re using. At TextileLab Amsterdam we have a BRM laser cutter, and are using Laser 5.3 software on the laser’s computer. I’ve written up my notes on how to use it, which are a work in progress but are linked at the end of this.
I imported my .dxf files from Slicer into the laser cutter software, rotated the file to that it fit better, and changed the size - for some reason, my file had opened in the laser software at a size 10 times too small, but there’s a resize function in the main menu tha tallows you to quickly resize.
When I imported my Slicer plans into the laser cutter software, it very handily had all the shape outlines in blue, and all numbers in red. This made it easy for me to set up different cut settings, for the outlines to be cut out, and the text/numbers to be engraved. Add note about outlines being cut before lacing holes. However, what I should have also done (or what would have been nice to have as a feature in Slicer) was separate out the lacing holes and the outlines. As you can (kind of) see in the image below, when the outline of a shape is cut out, sometimes the piece drops down out of the sheet material (or pops up a bit, or ends up at an angle). This means that you should make sure the outline of a shape is cut last, if it has engraving, or smaller pieces to be cut out inside.
In my case, the laser sometimes cut out the outline of a panel and then went back to cut out the holes, and because some of the panels had dropped lower than the sheet material, many of these holes didn’t cut out properly, and I had to punch through them with a needles (which was doable because I was using cardboard, but still not ideal!)
Cutting my whole model took about 3.5 hours in total
Step 5: Assembling#
Then came the part where I needed to stitch together 106 cardboard panels! I used a combination of thread and cord, and as the cord turned out to be hollow in the middle, I was able to fashion a needle for it by pulling some of the cord over the edge of a needle, and wrapping a small strip of masking tape around it:
I would describe this process as ‘sewing meets jigsaw puzzle’. As I had lost my original Slicer file, I knew which panel to attach to which, but it took a long time to figure out the overall shape, i.e. is this part I’m working on the top? The bottom? Is it one of her hips? I began to wonder if I’d ever figure it out, but it did mostly come together in the end.
My housemate’s cat was unhelpful and just wanted to sit on the cardboard.
In all honesty, I didn’t completely finish assembling my mannequin. As the shape started to come together, some of the smaller pieces buckled, and it became more difficult to sew panels together when I wasn’t easily able to access both sides. the edges of panels had a tendency to slide around and become unaligned, and liberal amounts of tape added to the inside didn’t help with this as much as I’d have liked.
At a certain point I decided that I’d stitch together as many panels as I could so that the mannequin would stand and look reasonably presentable, but that for the sake of my sanity I wouldn’t try and get eveyrthing done perfectly. So, she’s missing a few panels, and if you look closely you can see loose threads and tape showing, but hey done is better than pefect, right? ಠ‿ಠ
The cat is not convinced.
But I learned a lot and I did have fun doing it!
(Thanks to Irene Caretti for documenting this “where the f*** is the panel I’m looking for” moment)
Epilogue: 3D Scanning#
I am super behind on the 3D scanning part of this assignment, partly because of my own disorganisation, and partly because I was all set to use our 3D Systems Sense scanner, but it decided to stop working temporarily. As a placeholder while I get this part of the assignment done, here is Cecilia’s despair at the scanner’s refusal to work with us:
Update: Finally getting around to 3D scanning in week 5#
After a couple of super busy weeks, Irene and I finally got around to doing more 3D scanning. We had two new students with us who were joining Fabricademy slightly late, so the four of us did some scans with the Sense 3D scanner, which had decided to work again after getting some software updates.
An image from 3Dsystems.com, the manufacturer of the scanner, as I forgot to take a good picture of it…
The Sense 3D Scanner is an easy to use 3D scanner which has 1mm resolution, and can work at a distance of up to 1.8m away from the scan subject. It works in conjunction with its own software, and can export files in .obj, .stl format, among others. The downside of the Sense scanning system is that it’s not super cheap (ballpark 400 euro), and is not open source. The scanner works by projecting an infrared beam, and picking up reflected infrared rays with a webcam.
The Sense scanner connects to a computer, or mobile device, via USB. I noticed that this needed to be a usb 2.0 port, otherwise the computer would not detect the scanner. The computer that we were using for this at TextileLab Amsterdam is fairly old and didn’t have any USB 3.0 ports, but I suspect that these would also work just fine. But if you’re reading this and have no idea what I’m talking about and your computer doesn’t clearly label which kind of USB port is which, just try a couple of different ones, and don’t be discouraged if the first port you try doesn’t detect the scanner!
When you open the software for the scanner, it should detect the scanner automatically. then all you need to do is click ‘New Scan’ icon on the left hand of the screen, and then click again to start the scan. This will give you a three second countdown before the scan starts: handy!
To make a 3D scan, you have to move slowly around the thing/person you are scanning, or turn it very carefully. As we were using the scanner with a desktop (which is not mobile!) and the cord connecting it to the computer is quite short, we used a makeshift turntable available at TextileLab Amsterdam (basically a wheely chair with the seat replaced with a wooden board, wheels removed, and two wooden boards slotted under it for stability). Aka a health and safety official’s nightmare, but no Fabricademy students were harmed in the making of these scans.
While scanning, the scanner software shows you an image of what you’ve scanned so far. It warns you to stay still and go slowly if you’re not doing those things, and if you move too quickly it can lose track of what it’s supposed to be scanning, and will prompt you to stay still and go back to a previous position/angle it had already successfully scanned - if you do this, it usually just takes a few seconds before you can start scanning again.
As you scan, keep an eye on the computer screen to see how your scan is building up, and where you have holes - you can return to, and zoom in on, areas with holes so that these fill in.
When you’re happy with your scan, click the button on the right hand side of the screen to finish the scan. The software will then take a minute or two to create your 3D model, but when that’s done, you can click ‘Export’ - I exported our scans as .obj files.
After a first attempt to scan Irene, we were having issues capturing her head and neck, so we decided to move to another room where we would have more space, and where the person holding the scanner could stand on a stool to scan the head and neck. We found that the scanner didn’t quite work at it’s maximum range of 1.6m, but rather it was only able to be about 1m away from the scan subject. This made it more difficult to capture a person’s full body in one go, but we were able to move the scanner up and down to capture different parts of the body. Also, in retrospect, we could have knelt on the turntable and just scanned the upper body that way: that’s definitely something to try for a mannequin project where only the torso will be used!
Some other issues we encountered included:
Face alignment problems! Stephanie’s face does not look like this in real life, and I suspect that this mitch-and-max face effect happened because she didn’t stay still enough during the scan. I tested this by trying to stay super super still when I was being scanned, which worked well (but that’s only two data points, so not a solid dataset from which to draw a conclusion just yet!).
Surfaces that wouldn’t scan: I was wearing a black leather skirt and black shoes, and neither of these were possible to pick up with the scanner. The same happened with the top of my head, where my hair is darker. A quick bit of googling revealed that there’s a good reason for this: shiny surfaces reflect too much light, and dark surfaces too little, for the scanner to be able to reliably get an image of the surface. So it’s a good idea to avoid shiny textures and dark colours when scanning! Screenshot of my scan opened in Meshmixer
I don’t know why this happened, but Irene’s scan ended up mapping the fabric of her dress over the surface of her face, giving her a super interesting leopard print face.
As I had already made my mannequin, using a Makehuman scan that I had edited in Meshmixer, I decided that this not 100% successful result had still given me a decent grasp of how to 3D scan, and what can go wrong! so it was time to move on to the next project. As a final note, I was impressed with how well the Sense scanner picked up the detail on my necklace (which was made by Irish artist Kiki Na Art and features the German mathematician and theoretical physicist Emmy Noether)
- Meshmixer is free, but you need to create an Autodesk account to download
- Slicer for Fusion 360 is also free, but also an Autodesk product like Meshmixer
- Makehuman is open source
- My notes on how to use a laser cutter. These are a work in progress, hence they’re a google doc! I’ll hopefully update them and upload a pdf in the future.
- Here you can find a zipped file with my Makehuman model, .obj file of the torso shape from Meshmixer, my Slicer file, and a PDF of the plans exported from Slicer.