Alien Coin

thingiverse

This is a test of some software I built to transform a gray scale picture into a vertical profile. I drew the image in PowerPoint, made it into a 200 by 200 pixel picture, then the software converted it into a "coin," and after that, I printed using the output STL file. I'm thinking about printing an obverse and reverse separately and gluing them together back to back. If any of you skilled programmers out there are interested, please take my source code and modify it to minimize the number of triangles by merging adjacent triangles in flat areas. I just do a straightforward and simple triangulation of the pixel vertices - quick and efficient but files can become large and processing can be time-consuming. If you add that feature, send it back to me - I would greatly appreciate it! Here are some guidelines: Draw an image in PowerPoint or another graphics program, save it as a lossless bitmap format (BMP, PNG, etc.) with a resolution of less than 400 x 400 pixels (square). I usually use 200 x 200 because if you use too many it just takes a long time to process without any improvement in printed resolution. When creating the image, remember that only the image portion within a circular region inside the square bitmap will be converted into STL. Photos may not give you the effect you want because height and grayscale are unrelated in photographs. Take the ZIP file and use Visual Studio C++ to build the app. I used the Express version of VS because it's free. The GUI is pretty simple - just hit the load button, select the image file you want, and specify the coin base thickness and the mapping from grayscale (0-255 value) to vertical height above the coin base. For example, if you set Z min to 4 and Z max to 2, black (0) will map to a thickness of 4mm and white (255) will map to 2mm, giving a coin base that is 2mm thick with features sticking up 2mm above the coin flat surface. The software automatically masks off the image within a circle touching the limits of the image, which is why I call it a "coin." It always outputs a coin that's 100mm in diameter, so you can scale it to any size. By choosing the values in the grayscale min and max, and Z min and max, you can decide how the grayscale image maps to elevations on the coin.