I did not use any projection. I can understand that if I use projection, this precision issue may not affect me. But when I set the projection to geographic, SMS does not work well for me, it's easier to crash than no projection is specified. By the way, I'm using SMS 10.1.11, and work with scalar paving density mode on large scale. You are welcome! Anyway, I passed this issue by converting dxf to shapefile. But another problem is that when I working with shapefile, it is not correctly read sometimes. The current state of shapefile overlayed with previous shapefile edit history. I have to con