Computer-Controlled Cutting
Imperial Star Destroyer
In making press-fit cardboard, there is the all-important quantity of how much smaller to make the slots compared to the tabs. I found that 0.37mm worked well. Things got complicated with the slanted faces, which had slots that connected at an angle to vertically-aligned tabs. In this case I had to calculate the projection of the slots' widths on the horizontal plane, and have that match what I need for the tabs. It also took a few iterations to get the correct separation of the tabs that joined the bridge section to the triangular hull.
There were some problems with the laser cutter CorelDraw interface not reading the DXF files properly as vector graphics files. It is important to read in the file as a vector graphic, because one must be able to adjust line widths to "hairline" in order to tell the laser cutter only to make a single pass. Otherwise, the previous 0.37mm offset between slots and tabs would no longer hold, because the laser would cut off more material given thicker cut lines.
The solution to the importing problem was to open the DXF file in Inkscape, save it as a SVG file, and then open it in CorelDraw on the laser cutter side of things. I had to be very careful with scaling in doing this. If I drew the DXF file in LibreCAD using mm units, it was important to make sure this was preserved throughout all the conversion steps!
Addendum: from working on the final project it seems that this process distorts the dimensions of the drawing. Moreover, it turns out that LibreCAD drawings can be directly imported into CorelDraw as vector graphics, while at the same time maintaining proper scaling.
