Introduction to 3D Design - Autodesk AutoCAD 2013 Practical 3D Drafting and Design - page 12

Auxiliary tools
AutoCAD software is very precise and the correct application of these auxiliary tools
is a key factor for good projects. All users should be familiar with at least Ortho and
Osnap tools. Following is the application of auxiliary tools in 3D projects complemen-
ted with the first exercise.
OSNAP, ORTHO, POLAR, and OTRACK auxiliary
tools
Let's start with object snapping, probably the most frequently used tool for precision.
Every time AutoCAD prompts for a point, we can access predefined object snaps
(also known as osnaps) if the OSNAP button on the status bar is on. To change it, we
only have to click on the OSNAP button or press F3 . If we want an individual osnap,
we can, among other ways, digitize the first three letters (for instance, MID for mid-
point) or use the osnap menu ( CTRL + right-click). Osnaps work everywhere in 3D
(which is great) and is especially useful is the Extension osnap mode, which allows
you to specify a point with a distance in the direction of any edge.
But what if we want to specify the projection of 3D points onto the working XY plane?
Easy! If the OSNAPZ variable is set to 1 , all specified points are projected onto the
plane. This variable is not saved and 0 is assigned as the initial value.