2. Digital bodies¶

Research & Ideation¶

In this week, we will focus on exploring the human body in the digital environment. The human body, where we inhabit, is translated into its digital reflection, it becomes data, a cloud made out of tiny points made out of coordinates. Let's begin with defining what a Digital twin is. A Digital Twin is a virtual replica/representation of a physical object, or even a process, which is used to study both the real-life object and its simulated behaviour and interactions. Sometimes it is even possible to link both models to reflect any alteration of the real one.

Digitalization of a real-life object.¶

I will start with scanning myself through two technologies, photogrametry and Near-infrared scattered light scanning, both with advantages and disadvantages. The general process of scanning something goes like this: First you use specific machines for gathering all the data, either a camera or a proper 3D scanner, then the software does its magic and you get a model with which you can then post-process with another 3D design software such as Blender, Rhino, or similar. The post-processing is used to correct any artifacts and open meshes that the scanning might have left on the model, and also modifiying the model in the way we need it, like moving the fingers from a hand.

The photogrametry works through an app called Polycam which works by filming a video trying to capture all of the angles of said object.

Quick

It is better to isolate the object in order to get better results.
It is important to have good ilumination for better quality models.

The app is quite straigt-forward and easy to use, you open the app and start a new capture, then record whatever you may need to scan and the software, through dark magic called Gaussian splatting, does the rest. They have interesting payment plans for professional use, but this time i'm only using the free version, which allows 10 different scans, and let's you export it in GLTF format, which is a compact and fast file for sharing 3D models and scenes. The app also allows for cropping undesired data so the post-processing is faster.

Near-infrared scattered light 3D scanning This method has a much better and accurate result, but the scanning process takes much longer, sometimes there is even the need for markers, so the scanner knows where it is and has some reference as to what it is scanning. For this excercise I am using the Creality CR-Scan Raptor series.

References & Inspiration¶

It was the first time I used this technology in moving objects, as I have worked with some museums for generating digital twins of objects around the collection.

I kind of had the hang of how to use the scanner, but it was challenging as my hand, the one being scanned, was not as steady as i thought.

MakeHuman¶

For this week I also wanted to generate a virtual head with the MakeHuman software for fabricating a physical twin of a virtual object (¿?) the exact opposite of the 3D scanning part. MakeHuman is a tool for creating, designing and customizing virtual humans. Through the extensive list of modifiers we can create a realistic (virtual) human for use in the digital world, or in this case to export the head in order to bring it to the real-world.

After customizing the virtual person, the export process is very easy, through the Export menu. It is easy to select which kind of file is needed, the scale of the final model and even if the feet should be on the ground. Since I only need the head, I will use Blender to remove the rest of the body, and hope for the best. After removing the not-so-needed vertex, we need to close the gaps, so i'm using a simple tool called fill which is used like this: - First we select an edge of the hole. - Then, on the Select menu > Select Loops > Edge Loops, which will select al the edges around the hole. - Press Control + F, and the fill option should appear. For a simple hole sealing we use Fill, but if we need more complex geometry and more vertex, we can use Grid fill. - If needed, it is also possible to reduce the faces in the model with the tool Decimate for a lighter and easier to work object. - The final model can now be exported in the format we need, in this case it is also .stl

Et voilà! We now have a working 3D model for fabricating.

Slicing¶

It is time to bring the digital model back to the real world, in this case trough a tool called Slicer, which as its name suggests, takes the 3d model and makes tiny slices with different parameters as distance between the slices, if it's going to have some assembly, the thickness of every slice, etc. I will use the now out-of-date Slicer for fusion 360 to get each of the parts for laser cutting. The assembly will be done using a technique called Stereotomy which consists in assemblying simple solids into more complex geometries.

The menus work as it follows: - Manufacturing Settings Is the size of the canvas we will be working on. - Construction Technique Is the type of assembly that will be done on the 3d object, it can be Stacked slices, Interlocked Slices, Curve, Radial Slices, Folded Panels (like origami), and 3D slices. - Slice direction the name is self explanatory. - Modify Form Allows us to change the geometry of the original model, varying in thicknes, hollowing it, etc. - Assembly Steps Shows the name and order of each piece in the 2D cutting pattern. - Material Size In the bottom part it is possible to modify the size of the canvas, and also the thicknes of the material we will be using. - Get Plans Exports the file for cutting.

Laser Cuting¶

The software used for Laser Cuting at the Lab is called SmartCarve, and it has three main settings, which layer your object is in, how fast the laser should move for the cuting/scoring/engraving, and how much power should the laser have for the operation needed. If we have a high speed and low power, it is most likely to only burn a little bit on the surface of the material, which is useful for engraving or scoring materials. And viceversa, with low speed and high power it is more likely to burn so much of the material, that it gets cut. We will use the cutting parameters for the outside of each of the pieces, and the engraving parameters for the instructions, names and details for assembly.

Assembly¶

Fortunately both the design process and the machines, are very accurate so the assembly was very simple, and with the help of the assembly steps simulator in the slicer, we ended up with a 3D cardboard head, ideal for the sunglass collection.

I plan to use the 3D model of my hand for future projects, such as weareables or clothes.