Use 81 proportional (semi)magic 3x3 squares to produce a 27x27 magic square. Proportional means that all 81 (semi)magic 3x3 squares have the same magic sum of (1/9 x 9855 = ) 1095. Use the row and column coordinates of the 3x3 magic square. Don't use the numbers 0 up to 2, but 1 up to (81x3 = ) 243 instead. You must divide the row coordinates proportional over the 81 magic 3x3 squares. Use the table and connect each of the 9 rows to the other 9 rows to get  (9x9x3 =) 243 row coordinates:

Construct the 81 (semi)magic 3x3 squares.

Row coordinate +243x column coordinate = (semi)magic 3x3 square