Triangles (32×32 grid)
This origami tessellation is derived from my earlier Parallelograms Tessellation (flic.kr/p/2jcUzrE). By piecing together two symmetric "halves" of a parallelogram, you end up with a triangle. Since this tessellation lacks the vertical shift between molecules that Parallelograms have, it was much easier to collapse and a clean precrease was possible. Each triangle takes 8×6 grid units.
The model shown here is based around a 32×32 grid which leaves a margin of one grid unit along the top and bottom edges. You can see a version from 16×16 grid, much easier to collapse, at flic.kr/p/2jigWtS