OsnapZ Variable - 3d

OSNAPZ is an AutoCAD variable which determines whether or not Z is included when using object snaps. When the OSNAPZ variable is set to 0(default) Z is picked up with object snaps.

This can be problematic when placing pipe networks in a Civil 3D drawing, since usually you want Z to come from a surface. It also affects 3D Polylines and Feature Line creation.

Setting OSNAPZ to 1 will tell AutoCAD to ignore the elevation of the object you are snapping to. It will use the XY location, but Z will be your active CAD elevation (which 99.999% of the time = 0) or in the case of placing pipe networks - it allows Civil 3D to use the surface for the rim elevation of structures.