CAD hatch 2 GIS, shape and area changed, CAD lines don't

Hi, guys, i'm new here. When i make a hatch in Autodesk CAD, and then translate it into GDB via FME, then i use FME exporting to .dwg file, when i zoom in to a very large scale, the new geometry's boundary line doesn't fit the original one, the area of the hatch also changed a little, but the line or arc don't change when i do the same. Can anybody tell me how to make it right? THANKS!!