Unit Roundoffs and Their Effect on AccuDraw
Although you can set the X, Y, Z, Distance, and Angle fields by typing in values, AccuDraw also supports a roundoff feature that can force the new data point to a multiple of a set value. You can set AccuDraw's Unit Roundoff in the Coordinates tab section of the AccuDraw Settings dialog.
When you enable the Distance field in Unit Roundoff, AccuDraw acts as if there is an invisible grid in effect. The Distance Roundoff, however, always is calculated from the current compass location. In addition, at any time you can override this value by snapping to an element, or entering a value in the X, Y, Z, or Distance fields of the AccuDraw window.
You can use the Angle Unit Roundoff to lock elements along specific axes. For instance, setting the Angle Roundoff to 30 degrees assures that all elements placed will occur along one of the normal isometric drawing axes. As with the X, Y, Z, or Distance fields, at any time you can override this value by snapping to an element, or entering a value in the Angle field of the AccuDraw window.