With the construction lines feature, you can create construction lines that extend to infinity in one direction (rays) or both directions (xlines). You can also create circular construction lines.
Construction lines do not change the extents of the drawing, so their infinite dimensions have no effect on zooming or viewpoints. You can move, rotate, and copy construction lines the same way you move, rotate, and copy other objects.
You can use construction lines as references for creating other objects. For example, you can use construction lines to find the center point of a hole, prepare multiple views of the same object, or create temporary intersections that you can use for object snaps.
When you create construction lines, the program places them on layer AM_CL by default. Construction lines appear in red.
Additional options for creating and working with construction lines are as follows:
Automatic Construction Lines:
Using AMAUTOCLINES, you can create horizontal or vertical construction lines at contours. The program includes several options in the Automatic C-line Creation dialog box to create horizontal or vertical construction lines. When you use the AMAUTOCLINES command, the program considers only objects on layers AM_0, AM_1, AM_2, AM_3, and AM_7.
Trace Contour:
Using AMTRCONT, you can trace contours by using existing construction lines and circular construction lines in your drawing. To trace a portion of an arc or a circle, press ENTER while the command is running, then select the arc or circle. Then define the next intersection point. The program creates polylines automatically when you use the AMTRCONT command.
Projection On/Off:
Using AMPROJO, you can insert a projection crosshairs into your drawing. You can use the crosshairs as an aid for creating orthographic views.