Modular scale problem (not about grid scale)

i have problem with scaling in maya let say i have modular texture and i want to extract modular Pieces from it the question is how i can set scale for it like for example i want wall like 400 height and 600 width but the problem is i dont know how to scale it because after i exact it will have his own scale and maya scale always be 1x1x1 and i cant understand i hope someone know my question .

sorry for my bad english