circle-by-three-points ("a3")

See this command in the command table.

To access this command:

Edit ribbon >> Create >> Arc.
Home ribbon >> Create >> Arc.
Using the command line, enter "check-link-selected-strings".
Use the quick key combination "clss".
Display the Find Command screen, locate check-link-selected-strings and click Run.

Command Overview

Draws an arc defined by three points interactively in a 3D window. The first two points define the end points of the arc, and the third is a point that the arc passes through.

If no strings object exists in memory, a new object is created when this command is run, displaying details of the new object immediately in the Current Objects toolbar.

Snapping to Data

This command supports both left- (freeform) and right-click snapping. How snapping is applied depends on which of the three points is snapped.

If you right-click (snap) to define the start point, the arc will start at the snapped elevation, regardless of the currently active 3D section definition. If your first point is snapped:

Selecting the 2nd point (the arc end) with a left click adds the final point of the arc on the currently active section, potentially creating a spiral incline or decline. The third point (left or right click) defines the arc circumference, maintaining the gradual change from start to end point (which will always be on-section).
Snapping the 2nd point ensures the arc spans between the two snapped points and could, potentially, be completely off-section. The third click (left or right click) defines the extent of the arc.

Note: This command supports command line coordinates.

Command steps:

Run the command.
Click in a 3D window to define the start point of the arc.
Click to define the end point of the arc.
Click to define the point on the circumference.

Tip: Left-click and drag the third point to dynamically resize the generated arc, or right-click and drag to snap dynamically to nearby data.
Double-click or tap to cancel the command.