Have you been using the SNAP function to help in placing your objects in a straight line.
When you "check" the Snap box it will place your cursor in increments of the value of Snap Spacing, I believe the base (starting point)is the center of the map at X=0 and Z=0
So "Checking" the Snap box and let say the Snap Spacing is 100 (numbers are in feet)
You then will only be able to place Objects at 100ft marks.
0, 100, 200, 300, 400 etc.
Should be handy when copying a section of Objects ( like for a bridge )and then placing them at the end of this string.
Also having the snap box checked will keep your objects with whole numbers for their X and Z positons.
I didn't realize that.
Pokie