This instructable details work done by Matthew VanStaalduinen (a mechanical engineering technology student at UNC Charlotte) using 123D Catch, Meshmixer, and a VFlash 3D printer from 3D Systems to create (and modify) a physical representation of a virtual object from the game Homeworld 2.
Step 1: Tools and Software Required
• A video game where a full 3D view of the object can be obtained
• 123D Catch*
• Mesh mixer*
• A 3d printer (a V-flash from 3D Systems was used in this project) or access to one of the online 3D print services
• Flush cutter pliers
• A computer capable of running the software
*The software is free from Autodesk
Step 2: Select and Object!
The process we will be using is called photogrammetry. We will be taking photos of an object in real life or screen shots virtually of an object, and turning them into real solid parts using a 3D printer. The technology is advancing rapidly and has many uses in the engineering and medical fields.
Find an open area in the game where an all-around view can be obtained of the object. There can’t be any reflective parts or other objects blocking the view, also the object must contrast with the background. Then take a large number (depending on the object, this one took around 100) of screen shots of the object from all angles as to cover every surface of the object. If there are any tool bars or constants in the pictures, they will need to be cropped out.
Step 3: Create the Mesh
Load the screen shots into 123D catch as to the instruction of the program. Then submit the pictures, this may take a while to complete. This will take a few tries to get 123D Catch to function just right with stitching the screen shots together. Once the model in 123D catch is acceptable, save to model as an obj. file type. With a real or virtual object, a lot of work may be required to stitch adjacent views together. Your work and patience will pay off as you learn how to manipulate the reference points and generate better associations between the individual images. Once the object mesh looks good enough to catch the geometries, move on to the next step with the .obj file.
Step 4: Edit the Mesh
Import the file into Meshmixer. Meshmixer has several different tools that can clean up or modify the model. The main function of Meshmixer for this project is to convert the .obj file to a .stl file. The object for this project was printed as it was from 123D Catch, cleaned up, and very modified (rabbits head, horns, and arms added). It will take time to learn how to use the function in Meshmixer if you care to modify your model.
For the real object, using Meshmixer to edit the part is often a necessity because the mesh from 123D Catch will almost never come out printable, especially if the part is not hung from the ceiling. Parts that are placed on the ground will inevitably come out as a shell (very thin feature that is hollow). To fix this, Meshmixer has a repair function called “inspector”. This will close off any holes in the mesh that cannot be seen as well as fill the material into a solid object. Use this tool after every build before exporting as a .stl file.
Step 5: Print the Part
The .stl file that you want to print from Meshmixer can then be imported into the software for the 3D printer. In our case, a VFlash printer from 3D Systems. After placing and scaling the model on the build platform software, the model can then be printed.
Step 6: Part Cleaning and Finishing
The parts in the VFlash are built upside down on a build platform, along with requisite support structures. Once the new part has been built, it will need to be cleaned off the build platform with caution and the support structures removed (typically with flush cutter pliers).
This process is very time consuming and has a bit of a learning curve. The part that comes out will be better as long as you spend more time on it. There are endless possibilities on what to make 3D in this world and this is one of the methods. It is challenging but do not give up! There are many resources on each of the programs and it is highly recommended that you do a little research before beginning that next big build file.