Customizable space frame modules that can be joined and extended to arbitrary size. (Two assembled samples are shown in the picture.)
To be used with "Okkake Daisen Tsugi" (https://www.thingiverse.com/thing:5392796), a Japanese traditional wood joinery technique, for firm interlocking. Details of the design can be found in https://doi.org/10.31224/2338 .

The .stl files are just to show what can be printed; the actual use should follow the following steps:

• (i) find the right gap parameters for joints,
• (ii) print top grid module(s) and join them,
• (iii) print bottom grid module(s) and join them,
• (iv) print a necessary number and shape of diagonal modules and join them with plugs, and
• (v) join the three major components and insert tenon plugs.

Plugs for Okkake Daisen Tsugi and tenons can be printed with either of (ii)(iii)(iv) or separetely.

Due to the limitations of OpenSCAD, each of (ii)(iii)(iv) requires the editing of the source file but this is clearly indicated in the file.

Download both spaceframe.scad and tsugite.scad (from https://www.thingiverse.com/thing:5392796) and first find (and record) the right gap parameters by the test printing of tsugite.scad. Those number are used for 'eps6' and 'eps7' in spaceframe.scad.

Then print a single node and two diagonal beams to find the right gap for the interlocking of diagonals, tenons, and tenon plugs. Those numbers are used for 'eps1' to 'eps5'.

Note that top and bottom grids should be printed with different 'polarity' because one of them are used upside down.

Plugging of joints is not essential if the interlocking is firm enough, but is highly recommended especially when the load is not light and static.

Square pads on the ends of joints (as can be found in
spaceframe_grid2x2topNSEWpadded.stl) can be enabled (by setting 'pad' to 1) and are recommended because prints of this size and infill (which is supposed to be higher than models) tends to warp even when printed with PLA and PETG. If pads are not needed, set the variable 'pad' to 0.