how interpolate 3d points

i want to interpolate a cubic shape points

a=[18 30 30 18 18 18; 30 30 18 18 30 30; 30 30 18 18 30 30; 18 30 30 18 18 18];

b=[-10 -10 10 10 -10 -10; -10 10 10 -10 -10 -10; -10 10 10 -10 10 10; -10 -10 10 10 10 10];

c=[-10 -10 -10 -10 -10 10; -10 -10 -10 -10 -10 10; 10 10 10 10 -10 10; 10 10 10 10 -10 10];

Answer 1

[KSSV]

Read about gridata and scatteredInterpolant.