Here a line must be drawn in 3D from point A to point B. Only the white lines are presumed to exist: the yellow and red layers exist in the imagination of the draftsman.

Using the point filter object snap overrides allows one to draw such a line without any further construction lines.

1

Two sets of point filters are available:

  • Ordinate – .X, .Y and .Z – chooses one ordinate then the other two ordinates have to be supplied as a coordinate. For example, in the case where .X is used, I would interpret it as “Grab/remember the X value and then use the YZ value specified to complete the (X, Y, Z) coordinate”
  • Coordinate – .XY, .XZ and .YZ – chooses a coordinate then the other ordinate has to be supplied.

Start the line command, then

Shift + RMC > Point Filters > .X

When prompted “ Line Specify first point: .X of ”, select point A1. This “grabs / remembers” the x value of point A1.

When prompted “ Line Specify first point: .X of (need YZ) ”, select point A2. This then “grabs” the Y and Z ordinates of point A2.

The result is a concatenation of ordinates from A1 & A2 to yield point A as the start point of the line.

2

To indicate point B, “grab” the X and Y ordinates of point A

Shift + RMC > .XY

When prompted “ Line Specify next point or [Undo]: .XY of ”, type “@0,0,0”

This indicates that point A is use to “grab” the X and Y ordinates of point B.

When prompted “ Line (need Z) ”, select point B1 to “grab the Z ordinate of point B.