{"id":4376,"date":"2016-05-19T22:55:58","date_gmt":"2016-05-20T02:55:58","guid":{"rendered":"http:\/\/www.rocketshipgames.com\/blogs\/tjkopena\/?p=4376"},"modified":"2022-07-01T09:22:46","modified_gmt":"2022-07-01T13:22:46","slug":"3d-printing-for-wargaming-scratchbuilding","status":"publish","type":"post","link":"https:\/\/www.rocketshipgames.com\/blogs\/tjkopena\/2016\/05\/3d-printing-for-wargaming-scratchbuilding\/","title":{"rendered":"3D Printing for Wargaming Scratchbuilding"},"content":{"rendered":"

Recently I got a 3D printer and have been having a great time with it. My more general thoughts<\/a>\u00a0about the technology I’ve already posted. Here I present a quick walkthrough of one of my immediate, highly critical and urgent, applications for the tool:\u00a0Making\u00a0detailed parts for miniatures wargaming terrain.<\/p>\n

Design<\/h2>\n

Recently I\u00a0scratchbuilt a small\u00a0facility<\/a>\u00a0for a new set of terrain I’m working on for my club’s upcoming LibertyHammer<\/a> event. One of the little bits built\u00a0to provide some detail and texture to the model’s\u00a0overall look is a simple antenna cluster.<\/p>\n

\"Scratchbuilt<\/a>

Scratchbuilt antenna array.<\/p><\/div>\n

That prototype\u00a0turned out pretty\u00a0well, so now I’d like to have a bunch of them to stick\u00a0on various buildings in the set. They’re not hard to make so they’re not worth the hassle, cost, or\u00a0time to resin cast (though it would be straightforward to do so because of the verticality and flat bottom plane of the shape).\u00a0With the 3D printer though I can make a tradeoff: It’ll actually take longer to produce, almost\u00a030 minutes on my printer at high detail versus maybe 10 minutes for me to make by hand. But I\u00a0can do other things in that time, and they’ll\u00a0be more consistent, more detailed, and I don’t have to scrounge around for\u00a0supplies and components.<\/p>\n

To do so of course I have to create a 3D model. For this project I used TinkerCAD<\/a>, a simple\u00a0browser-based 3D\u00a0computer aided design (CAD)\u00a0program\u00a0from Autodesk<\/a>. The end result is faithful\u00a0to the scratchbuild, with just a few more details.<\/p>\n

\"The<\/a>

The finished antenna array in TinkerCAD.<\/p><\/div>\n

TinkerCAD is essentially a constructive solid geometry<\/a> modeler. Its core operation is constructing\u00a0complex shapes by adding\u00a0and subtracting simpler shapes\u00a0to and from each other (unfortunately it does not seem to support the third constructive geometry primitive operation, intersection). For example, to put a hole through\u00a0a cube you take a cube and a cylinder and subtract the latter. To make a farm\u00a0silo you would take a cylinder and add a sphere sunk halfway into the top.<\/p>\n

One advantage of this paradigm is\u00a0that the final product\u00a0is\u00a0guaranteed to be solid<\/em><\/a>. In mathematical terms, every point in space is completely determined to be inside, outside, or on the surface of the shape. Intuitively, the 3D\u00a0shape is watertight, there is no way to pass between\u00a0the common sense\u00a0exterior and\u00a0interior. This\u00a0property is critical because it’s essentially required in order to\u00a0print a model. Although there are other approaches to working with solids besides constructive geometry, not all\u00a03D modeling approaches are based on solid forms and may not\u00a0guarantee that\u00a0property\u00a0and be\u00a0as directly applicable\u00a0to representing physical artifacts. For example, many tools oriented toward video game and animation modeling are based around manipulating arbitrary 3-dimensional meshes of polygons, which aren’t\u00a0necessarily solid and may not be printable because no algorithm can determine what is inside and what is outside the piece.<\/p>\n

Another feature of constructive solid geometry is that it’s comparatively easy to make many kinds of\u00a0modifications to the part later on, because the sequence\u00a0of steps and feature composition of the part is naturally retained in its model.<\/p>\n

A downside of constructive\u00a0geometry though is that it can be difficult or actually formally impossible to create\u00a0some complex shapes. Fortunately though, the\u00a0style is well suited to making many types of\u00a0mechanical parts, as well as many kinds of\u00a0wargaming models, especially mechanical or industrial terrain.\u00a0The antenna cluster for example is mostly just a few cylinders of varying sizes, a base plate, a\u00a0negative cylinder to create a\u00a0pocket forming a\u00a0partial wall around the antennas, and another pyramidal hole slicing an angle off the top of one antenna.<\/p>\n

\"Constituent<\/a>

Constituent parts of the antenna array model. The gray semi-transparent parts are holes, negative shapes. The other colors have no meaning.<\/p><\/div>\n

Printing<\/h2>\n

The part is then exported to STL, a STereoLithography file<\/a>. This is one of the primary file formats common across\u00a0CAD software\u00a0and is ubiquitous in 3D printing. Stereolithography<\/a> is actually one of the earliest forms of 3D printing, and the basic principles are still widely used, particularly for very high resolution printers. One of the reasons for the STL format’s enduring popularity beyond those early tools though is its simplicity: The entire model is represented as a collection of triangles making up a polygonal mesh. That’s essentially a lowest common denominator for\u00a0working in\u00a03D, so\u00a0it’s easy for\u00a0software developers to\u00a0import and export.<\/p>\n

\"View<\/a>

View of the STL triangular mesh, from viewstl.com.<\/p><\/div>\n

Like most home 3D printers, mine is a fused deposition modeler<\/a>. A strand\u00a0of material, usually some type\u00a0of plastic filament but not always, is heated and extruded through the printer head. Servos move that\u00a0printer head or part workbed around to outline\u00a0and fill a single horizontal 2D slice\u00a0of the part. The head is then moved up\u00a0relative to the workbed\u00a0to deposit another slice on top of that. Working from bottom to top, eventually a 3D part is constructed.\u00a0Slicer software is responsible for taking the STL file and cutting the shape\u00a0up into thousands of layers, then\u00a0generating the movement commands to\u00a0drive the print head.<\/p>\n

\"My<\/a>

My Lulzbot Mini.<\/p><\/div>\n

\"The<\/a>

The antenna ready to print in Cura, a popular slicing and control package.<\/p><\/div>\n