I assume that your problem is that you don't get enough sub-boxes. The number of partitions refers to partitions per dimension, right? So 2 partitions yield 8 sub-boxes, 3 partitions yield 27 sub-boxes and so on.
Then you must have three nested loops, one for each dimension:
for (int k = 0; k < NUMBER_OF_PARTITIONS; k++)
for (int j = 0; j < NUMBER_OF_PARTITIONS; j++)
for (int i = 0; i < NUMBER_OF_PARTITIONS; i++)
{
Vector3 minInnerAABB(
minPointAABB.getX() + i * l,
minPointAABB.getY() + j * l,
minPointAABB.getZ() + k * l
);
Vector3 maxInnerAABB(
minInnerAABB.getX() + l,
minInnerAABB.getY() + l,
minInnerAABB.getZ() + l
);
// Add the inner AABB points to a container for later use.
}
}
}
Alternatively, you can have one huge loop over the cube of your partitios and sort out the indices by division and remainder operations inside the loop, which is a bit messy for three dimensions.
It might also be a good idea to make the code more general by calculating three independent sub-box lengths for each dimension based on the side lengths of the original box.