FITARC command

Fits an arc or a circle to entities.

BricsCAD Lite; BricsCAD Pro; BricsCAD Mechanical; BricsCAD BIM


Draws an arc or circle fitted to one or more entities. The command minimizes accumulated perpendicular distances to the points of the selected entity(ies).

A realistic use case is a production company of advertisement cardboard. Typically, the 2D CAD files to pass to the cutting machine are imported from other design software, where polylines and splines are the typical 2D curve entity types. Take the example where the machine has to cut a half-circle in the cardboard, and the half-circle is represented by a polyline with a lot of small subsequent linear segments. When passing this drawing to the cutting machine, the machine will make a sequence of many of small cuts. After each cut, the machine has to stop, change orientation and restart. For each stop-change-restart action, there is a chance for errors. This would not only lead to a much longer cutting time, also the resulting cut will be suboptimal and look rough. In this case, FITARC could be used to turn this polyline into an ARC, leading to one fast and smooth cut operation.


This command opens the Fit Arc command panel.

The options within the FITARC command are the same as the options in the Fit Arc command panel.

The entities and the results of this command are shown in the examples below:

  1. Points used by the command to fit the arc.
  2. Arc fitted to the points.
  1. Polyline used by the command to fit the arc.
  2. Arc fitted to the polyline.

Options within the command

use Entire drawing
Use all entities in the drawing as input.
Fit in 3d

This option applies when one or more input entities do not lie in the XY-plane.

If checked, the resulting arc or circle is created in 3D space, otherwise the input entities are projected onto the XY-plane first.

Note: The XY plane used for projection is the one of the current UCS (User Coordinate System). This allows the user to make the fit in any plane.
Delete original entities after fitting
When this option is set to Yes, the initial entities are deleted.
maximum Gap angle
Defines the threshold value for the maximum angle gap between the characteristic points of the input entities. If the maximum gap angle is larger than the threshold value, an arc is created. Otherwise, a circle is created.
selection options (?)

Allows to choose a selection method. See the SELECT command.

Note: The options Use entire drawing, Fit in 3d, and Delete original entities after fitting can be set using the system variable FITLINEFITARCMODE. The option Maximum gap angle can be set using the FITARCMAXGAP system variable.