Rectangular Tessellation

ilox_linear places interlocking cell pairs on a rectangular grid: cell A instances (green) on the grid points over one substrate, cell B instances (blue) on the grid midpoints under the other. An extension factor stretches cells along Y to close the gaps a square lattice would otherwise leave.

The rails lock the halves against pull-off and across the rails, and slide freely along them: the halves assemble by sliding one onto the other.

Source: examples/simpleUsage/simpleUsageRectangular.scad

use <../../iLOX.scad>;

// Width / height of the unit cell
width = 5;
height = 10;

// Division line as [x, y] points
div = [ [ 0.5, 0 ], [ 0.3, 0.1 ], [ 0.3, 0.4 ] ];

// Gap between the interlocking cells, in mm
clearance = 0.2;

// Voids cut out of the cell: a list of polygons
voids = [ [ [ 0.7, 0.8 ], [ 0.7, 1 ], [ 0.3, 1 ] ] ];

// Grid size, substrate, and gap-closing extension
grid_n = 5;
grid_m = 4;
substrate_height = 3;
extension_factor = 0.5; // [0:0.1:1]

ilox_linear(width = width, height = height, div = div, clearance = clearance,
            voids = voids, grid_n = grid_n, grid_m = grid_m,
            extension_factor = extension_factor,
            substrate_height = substrate_height, part = "both");

Key parameters:

• clearance — the gap between the two interlocking halves in mm, measured normal to the division line. A feature of the line too small for the clearance, such as a barb narrower than it, is lost in the offset, and the gap there is wider.
• tip_clearance — optional gap between each cell’s tip and the opposite substrate, in mm, below half the cell height; defaults to clearance, and 0 gives full-height cells. A large value can cut a cell short of interlocking, and a clip just above a horizontal face can leave a thin ledge.
• part — "both" to view the joint, or "A" / "B" to export one printable half (print B upside down).
• grid_n, grid_m — number of grid points in X and Y; grid_n at least 2, since the B rails sit between the A rails.
• extension_factor — stretches cells along Y (up to one cell width) to reduce the gaps between rows.
• substrate_height — thickness of the solid backing each side of cells sits on.

Set show_ucell = true in the full example file to inspect the 2D unit cell with ilox_cell_designer before tessellating it.