This might be typo.

[Seongje Jang]

1130th line on nanort.h

pos = bmin[j] + (i + 0.5f) * bstep[j];
should be
pos = bmin[j] + (i + 1.0f) * bstep[j];

There are some comments above this statement.

  //
  // Split pos bmin + (i + 1) * (bsize / BIN_SIZE)
  // +1 for i since we want a position on right side of the cell.
  //

This comment dosen't correspond to the below line.
I guess one of them is wrong.

[Syoyo Fujita]

Thank you for finding an issue!

Its now fixed.