Marching cubes algorithm on own x,y,z data

Hello all,
I am using marching cubes lewinar algorithm for surfaces reconstruction in 3d . I have data in the format of x,y,z coordinates. How to convert it into 3d volumetric data.

suppose i have

Note: I have taken 3 points just for example purpose

marchine cubes algorithm requires data in 3d numpy array. plz help