3D Scanning Process: Capture Objects, Edit, and Slice Them
There are three main options for preparing 3D models for 3D printing. One is using a 3D modeling software, such as SelfCAD. This is one of the popular methods, allowing you to tweak the design exactly according to your requirements. 3D modeling was once reserved for professionals, such as engineers and artists, but with SelfCAD, anyone can get started with ease. You don’t need prior experience in 3D modeling to create your files. The many interactive tutorials available make learning easy.
The second option is to download them from 3D model websites, such as Thingiverse, Printables, and MyMiniFactory, among others. You can browse those websites and search for the specific files you need. After downloading, you can edit and adjust them in SelfCAD before 3D slicing. The third option, which we will examine in detail in this article, is 3D scanning.
What is 3D Scanning?
3D scanning involves capturing the physical shape and geometry of real-world objects using either a handheld 3D scanner or a smartphone equipped with a dedicated 3D scanning app. The 3D scanner captures precise measurements of the object's surface, and the resulting data is saved in a mesh file format, such as STL, OBJ, PLY, or another format, which can be exported to CAD software for editing, and slicing. 3D scanning is great for replicating the already existing objects without the need to model them from scratch. This is especially useful for reproducing parts that may be difficult to measure manually or are organically shaped, like sculptures, mechanical parts, or even the human form.
Reverse Engineering Through 3D Scanning
Reverse engineering through 3D scanning is utilized for product design, quality control, and restoration purposes. Engineers can scan existing parts to redesign or improve upon them, ensuring compatibility with current systems. It is also a key tool in fields such as automotive restoration, aerospace, and medical prosthetics, where precise customization or replacement of parts is necessary. When combined with 3D printing, the process becomes even more powerful, enabling scanned objects to be digitally modified and physically reproduced, thereby streamlining workflows from analysis to prototyping and final production.
3D Scanning and Editing Files in SelfCAD
My first 3D scanner was the Revopoint MetroX. I was glad to receive it from them, and although I was new to 3D scanning, I quickly saw its potential and wished I had obtained one earlier. It opened up a whole new way of creating printable models without having to start from scratch in a CAD program. I went through the user manual and watched their video on installation.
After assembling and downloading Revo Scan 5, the recommended software, I was ready to start 3D scanning. The first design I started 3D scanning was the Sample object that came with the scanner.
It came out well. However, some unwanted sections at the bottom were accidentally captured by the scanner.
Additionally, there were holes at the top of the head that needed to be filled.
I would have done the editing in Revo Scan 5, but I exported the model to SelfCAD as it’s the one I am familiar with. To do this, I went to File > Import, then navigated to the location where I had saved the file and imported it. SelfCAD also supports various file formats, including OBJ, 3MF, PLY, FBX, and GTLF.
After importing, I then started fixing the design. I started by cleaning the mesh and removing the unwanted parts. I began by selecting the unwanted parts in the file using the Marquee selection tool.
I then pressed the delete button on my keyboard to remove them.
Another alternative method is to use the Cube selection tool to crop the object only, as shown below.
Then, I went to the Utilities > Split.
After processing the split, a new mesh will appear in the Objects section. Select the original design and delete it; you will then be left with the cropped section, as shown below.
There were still a few unwanted parts remaining on the file that required cleaning, like the part below.
To remove it, I had to select it using the Polygon section tool with the Deep selection option enabled, and I increased the tolerance to 9 so that the entire part would be selected appropriately, then I deleted it. Check out the video below to learn the entire process.
Further Cleaning of the 3D Model
The next step is to fill in the holes on top of the design. Below is the file before filling in the holes.
To fix this, go to Tools > Fill Polygons, and start processing.
After finalizing, we successfully filled the holes.
The next step is to simplify the object to reduce the polygon count which have been added when using fill polygon tool. This is helpful in speeding up editing, as well as making it easier to slice and edit. To do this, go to Modify > Simplify Object and start simplifying.
If you would like to learn more on how to simplify objects in SelfCAD, you can check out the video below.
Next, we will use the sculpting tools to sculpt and smooth the top section so that it looks like the rest of the surfaces. Activate the sculpting tool from the Sculpting option in the menu bar, then use the various brushes to fix the model. Thereafter, use the Resolution tool to smooth the file further and adjust the level of details. Check out the video below to learn the entire process.
The final design I achieved is shown below.
Next, we will need to analyze the model and fix any geometric issues. For example, we will need to identify duplicate vertices or edges, fix small holes or gaps in the mesh that may not be visible physically, remove inner faces, optimize the mesh for improved performance, and resolve non-manifold geometry that can result in slicing and 3D printing issues. To achieve this, we will utilize the Geom Clean Tool, located in the Utilities section. When you click on it, the cleaning process will begin.
You will also see the issues being fixed in the mesh.
When the software finishes cleaning, you will also see the specifics of what has been fixed in the mesh.
The next step is to slice the file and generate the G-code to send to the 3D printer. To do this, click 3D Print, and a new window will open with the slicer. Select your 3D printer, and the slicer will launch. You can then apply the necessary settings. To learn how to slice STL files in SelfCAD, check out the video below.
3D Scanning Using a Phone
If you don't own a handheld 3D scanner, you can use a phone app to do the scanning and then import the 3D scans into SelfCAD. A good example of such an app is Polycam. It allows you to create 3D models using your phone’s camera by either capturing depth data (on devices with LiDAR) or through photogrammetry, where you take several photos, then stitch them together to form a detailed 3D mesh. The first project I worked on was for Valon lotion. The app captured the design shown below, but it also captured the background.
To clean it up, I will need to import it into SelfCAD.
The file below was also 3D scanned in Polycam.
You can check it out here. https://poly.cam/capture/f4a53d78-e506-4a5f-8beb-660436cc2c3f
Polycam provides the option to export in commonly supported file formats that are compatible with SelfCAD.
To be successful in 3D scanning using Polycam, it is essential to take as many photos as possible from different angles around the object. The app relies on photogrammetry, a technique that involves analyzing and stitching together multiple overlapping images to reconstruct a detailed 3D model. The more photos you take, especially from varied perspectives, the more accurate and complete your scan will be. Try to move steadily around the object, capturing every surface, including hard-to-reach areas like the top and bottom, to avoid holes or distortions in the final model.
Lighting also plays a key role in capturing quality photos. Ensure the object is well-lit with soft, even lighting to avoid harsh shadows or blown-out highlights, which can confuse the photogrammetry process. Avoid reflective or transparent surfaces, as these can be difficult for the software to interpret correctly.
If you would like to learn more about preparing 3D scans for 3D printing in SelfCAD, you can check out our playlist on 3D scanning for 3D printing.
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