One of the critical sub-hobbies of wargaming is acquiring and preparing miniatures. There are many highly detailed miniatures sculpted by expert craftsmen and precisely casted to preserve the fine details available to purchase. Unfortunately, my budget for wargaming doesn’t allow for great miniatures and my painting skills wouldn’t do them justice anyway, forcing me to either design my own or use 2D counters or stands. I do have some basic 3D modeling skills developed through planning my house so I embarked on 3D design. This will not be an explanation of design theory. Some of that is covered in my contribution to the Second Portable Wargame Compendium. This will be a more technical walkthrough of how I convert models designed in SketchUp to ready to print files. In general the steps from design to print are as follows: Design, Export, Repair, Slice, Print.
The first step is the actual modeling. I do all my modeling in SketchUp. There are other free options that are better than SketchUp. Fusion 360 is better than SketchUp for highly precise and technical models and Blender is much more capable of modeling organic curves and can behave much more like digital modeling clay. Both have learning curves that can be overcome but will take practice. Most basic work can be completed using only the free suite of tools in SketchUp. I have expanded my SketchUp skills be searching out how-to’s on the internet.
After you are satisfied with the model the next step is exporting it in a format that a 3D printer can use. All modern 3D printers use the .stl file format. SketchUp online now has a simple downloading function that saves the file to your drive as .stl files.
If you’ve designed your model in Sketchup and downloaded it as an .stl file, you may need an additional repair step before you are ready to print. For 3D printers to process a. stl into the type of code it requires, the item being printed must have a continuous exterior skin with no internal geometry. If (like me) you’ve designed your models by overlapping many simple shapes into complex shapes, the model will have a lot of internal geometry. This will certainly confuse the slicing software to the point where it will produce unusable slicing or refuse to slice entirely. Luckily on Windows PCs there is a free program called 3D builder. If upon opening the .stl file an error message about improperly defined models appears, you will need the repair step. Fortunately repairing the file is as simple as clicking the error message. 3D Builder does the rest. You will need to look at the file in detail after 3D builder repairs it. The software tends to fill in very small, sharp “canyons”. Most of the “fixes” it makes will not be significantly noticeable after printing, but rework on the modeling will be required if 3D builder isn’t giving good enough results. Once you are satisfied with the repaired model, save the repaired file as another .stl.
Now that the file looks correct, the next step is to translate it into something useful for the 3D printer to use. 3D printers work by squeezing layers of molten plastic on top of each other. Eventually these very short layers build into the shape of the final product. The purpose of the slicing software is to generate the path and instructions that the printer should follow as it squeezes out the layers. If you’re familiar with MRI imaging, each image is essentially a layer. I use Cura as my slicer. It is again free to download and use. There are many settings to tweak and each can have significant impacts on the success and quality of the print. Most 3D printing communities will have proven profiles of settings that can serve as a starting point. You will still need to tweak it for the exact brand/color of filament used. I’ve needed to adjust printing temperature about 7% even in the same brand to account for the differences in color. Mastering the exact settings that work for your printer and filament at the required level of detail can be a hobby all to itself. Once the model is sliced, save the g-code to whichever data storage drive your printer uses.
Finally, the model is ready for printing. Follow the printer’s instructions for startup and beginning a print. I’ve had best results letting the heated bed warm up for a few minutes longer than the printer would do on its own. It gives the whole bed a better chance to equalize in temperature and I think it reduces the number of prints that fail by becoming disconnected from the bed. The next step is waiting patiently for the print to complete. This will likely take several hours. Checking on the printer from time to time is good, but watching the entire print process is certainly unnecessary. If there is a failure mid-print, being available to stop it is certainly preferred to wasting the plastic that will be consumed in continuing to print an already failed model. After the print is complete, let the model set on the print bed until it fully cools (reduces chance of warping) and remove it.
At this point the print can be treated like any other plastic model. If there is support material required to allow overhangs to print, the supports will need to be removed. The model can be lightly sanded to remove any bumps or inconsistencies. If the model is to be painted, a good coat of primer is very important. The most common plastic used in 3D printing (PLA) is very slick and will require several coats of acrylic paint to get desirable results without primer.
I hope this has brought some clarity to the 3D printing process to anyone considering purchasing a 3D printer for wargaming uses. If the process seems too daunting, there are many small businesses that will take over the process starting at the repair step. If you only need a few models printed, this will certainly be less expensive than purchasing a printer and dealing with the frustration of failed prints yourself.
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