Dual regular triangular dipyramid derived organic shape 18

grabcad

I started with a regular triangular bipyramid and converted it into a frame made of pipes by turning each edge into a hollow cylinder. The pipes connected at joints where the vertices of the original bipyramid used to be. Taking this pipe frame, I rotated a duplicate 144° around its central axis, then intersected the copy with the original shape. Next, I took the resulting shape and spun it another 180 degrees around the same axis before merging it with its mirrored self. Finally, I smoothed out the edges of this final composite shape by filleting them.