This paper addresses the correlation between the change of file size and the scanning path build time by the slicing height of STL file. Though the study about STL file has been achieved quite actively scanning path build time using STL file is not investigated so much to be satisfied. The file size depends on the number of polygon created by the slicing height specified. And this number of polygons increases in a regular rate. The correlation between the number of polygons and the scanning path build time is examined and verified.