5. 3D Scanning and printing¶
- Design and 3D print an object (small, few cm3, limited by printer time) that could not be made subtractively
- 3D scan an object (and optionally print it)
Reasons for 3D-printing¶
3D-printing is an additive process, which means that there is very little waste product. On a 3D-print, only time there is any waste would be if any supports are printed to help with things like overhangs. With subtractive processes like vinyl cutting or laser cutting, there is always going to be some materials between parts that will be too small or oddly shaped to be useful for anything.
There are, however, some disadvantages including build size. This is important since it is not very feasible to print huge parts without an industrial-sized printer. Standard printer beds are only ~10 inches long on each axis.
This is the workflow for using a 3D-printer:
Designing and 3D printing an object¶
Since we have to make something that could not be made subtractively, Neil mentioned that we should design something that is in another element. I interpreted this as something being “trapped” in something else. Because of this, I decided to make a cube with a ball stuck in the middle. This could not be made any other way because if you made the ball and box separately, it would be impossible to place the ball inside since each side is larger than the width of the spaces.
Here are some images of the CAD file in Fusion360:
o This is a photo of my screen in Cura which is the software we use to upload the file to the printer:
These are some photos of the print:
Here are some different angled photos of the final print with the supports removed:
Scanning and object and printing it¶
This software was very easy to use and the result I had was very good. I decided to scan a vintage tennis racquet and the cover I had in my room. I took around 600 photos from as many angles and distances I could. The first step in making this rendering was to make all the points from all those different camera angles and let the computer put those together. I did this by clicking on the “chunk” of photos and choosing “process → align photos”.
After this, I wanted to make a mesh of these points so that I could export this scan to different softwares such as Fusion360. I did this by selecting the chunk again and choosing “process → build mesh”. This basically connects all the points to have smooth surfaces. The individual strings of the racquet did not turn out very well, but I was not disappointed or surprised by this since they are very thin.
I then saved the scan to my computer. Since it was now a mesh, I could use the 3D Viewer app that is automatically downloaded on all compatible Windows machines and I was able to see the rendering. There is an option to choose different color schemes, so I selected different color palettes to highlight contrast.
After that, I decided to bring the mesh into Fusion360 to clean up the scan since it picked up a lot more than I desired. This included things like my carpet, chairs, etc. I did this by selecting “mesh → erase and fill” and then just selected all undesired areas.
I did not have a very good experience with this software. The computer I use is a Surface Pro laptop that is about 4 years old, meaning that this computer is not powerful enough to run advanced rendering softwares such as Meshroom. I attempted a couple of different renderings with varying amounts of photos. First, I attempted to scan jumbled earbuds that I had on my desk. I took about 250 photos, but this rendering took way to long and when it eventually finished, it was not very impressive. I suspect it did not work very well since the tangled wire is definitely complex shape to design and extract from images. For my second test, I attempted to scan a small hammer with about 100 photos, in hopes that the simpler design and less photos would render a simpler scan and take less time, respectively. This also did not work since there was not enough data from my small amount of photos.
After my fruitless attempt to use Meshroom, I decided to try out a mobile scanner. I looked online and I found several credible and good scanning apps for mobile phones, however most of these apps were only compatible with iOS. I have a Google Pixel 3, so my selection was greatly limited. I decided to try out Qlone and attempt to scan a small hammer we had in the lab. All I had to do was print the sheet of paper with the grid, place the hammer on that sheet, and start rotating around the object. As you can see, the general shape and colors worked well, especially the handle. However, since the top of the hammer is made out of metal, there was constantly a reflection and the software had a difficult time determining the true shape of the hammer.
- Test the design rules for your 3D printer(s)
Details about this week’s group assignment can be seen at this link. I worked a lot on the definitions of various terms and describing the limitations of our printers.