Table 1.

Mathematical characterisation of P-surface graded structures and their relative density.

TPMS	Periodic trigonometric function	$C$	Relative density
P	$\varnothing \left(r\right)=\cos \left(2\pi x\right)+\cos \left(2\pi y\right)+\cos \left(2\pi z\right)+C$	0.04z	Graded 45–55%
		0.08z	Graded 40–60%
		0.16z	Graded 30–70%

TPMS = triply periodic minimal surface.