How to fill a volume with a procedurally generated 3d voxel grid?

I'm trying to make a script that takes a cube, raycasts out of each face, and instantiates it until the ray collides with something.

I've been playing around with generating voxel grids from a boolean array, as in this question, but I can't quite figure out how to generate the grid to fill a space.

The basic grid code:

 var voxelArray : boolean[,,] = new boolean[10,10,10];
 var cube : GameObject;
 
 
 function Start()
 {
     
     for(var z=0;z<10;z++) {
 
         for(var y=0;y<10;y++) {
 
             for(var x=0;x<10;x++) {
                 voxelArray[x,y,z] = true;
                 var temp = Instantiate(cube,Vector3(x,y,z),Quaternion.identity);
                 temp.name = "voxel"+x+y+z;
             }}}