A shell style inverted gyroid.
I had this already printed - see:
However it s not too easy to remove stuck printing powder - see:
What's the difference?
This one is an isosurface as is. It has no clipping conditions nor any sophisticated postprocessing nor optimization. The shape is - as is -purely the result of one single formula. Hence it's outer areas have become a bit thicker than you might expect.
9.572 w x
9.578 d x
3.769 w x
3.771 d x