Exporting to STL

STL, which stands for Standard Triangulation Language or Standard Tesselation Language is a file format used by stereolithography software. STL-Files describe the surface of 3-dimensional objects. BURRTOOLS can export single shapes into STL files so that 3D printers can quickly fabricate prototypes of them.

The main menu entry Export - STL opens the window seen in Figure StlExportWindow. The window has shape selector, a 3-D view of the selected shape and some parameters that control the shapes created. The exact parameters depend on the grid of the current puzzle.

Figure: The STL-Export window

Filename and Path control the name and position of the generated file. Those are common parameters for all grids.

For cubes there are the following parameters that control the shape of the generated pieces

• Cube Size: controls the base length of the created cubes.
• Bevel: controls the size of the bevel
• Shrink: allows a gap between the pieces, so that it is actually possible to assemble them. If the shapes were made to correct sizes they would touch, making movement impossible.

For spheres the parameters are as follows:

• Sphere radius: controls the gap between the centres of the single spheres. It also is the maximum radius the spheres can have. This value is in output units
• Connection radius: controls the radius the connection of the spheres has. As the spheres mathematically only touch in one point connectors need to be added. Those connectors are cylinders. The radius of those cylinders can maximally be so that they touch one another. If this value is 1 then the cylinders have their maximal radius, 0 would mean no connection
• Curvature radius: controls the radius of the transition between sphere surface and cylinder surface. If this value is 0 no transition is done and there will be a bend in the surface. If the value is 1 the maximally possible area will be used to go from sphere surface to cylinder surface. When there is only little or no space for the transition (e.g. when the connection radius is close to 1) there might be a bend, even when this value is close to 1.
• Offset: just like with the cubes this makes the spheres smaller to make the puzzle actually assembable. This is in output units. Keep the values small if you want to have working puzzles.
• Recursions: controls the number of used triangles to approximate the surfaces. A value one bigger will result in approximately 4 times as many triangles and accordingly smoother surface but also bigger STL files. Don't make it too big as it will result in long calculation times and huge files!

The STL-Export right now works only for cubes and spheres. Triangles and the rhombic grid are not supported. Also the shapes to export must not contain any variable voxels.