### Constructing a Best Fit or Best Fit Recompensate Ellipse

A "best fit" ellipse can be constructed from three or more features. The ellipse lies in the current working plane. The best fit construction method takes the actual measured points, rather than the ball's center (as is the case of best fit recompensate). In both cases PC-DMIS computes a least squares ellipse, one for which PC-DMIS minimizes the average squared distance from the data points to the ellipse.

To construct a Best Fit Ellipse or a Best Fit Recompensate Ellipse:

1. Access the Construct Ellipse dialog box (Insert | Feature | Constructed | Ellipse).

2. Select either the Best Fit or Best Fit Recompensate option (shown as Best Fit and BF Recomp).

3. Select at least 4 features or a scan or a set comprised of at least four points.

4. Click the Create button.

The Edit window command line for this option would read: CONSTR/ELLIPSE,BF,feat_1,feat_2,feat_3...
(Uses the actual measured points for construction.)
or
CONSTR/ELLIPSE,BFRE,feat_1,feat_2,feat_3...
(Uses the center of probe for measurement.)

More:

Remove Outliers / Standard Deviation Multiple for a Constructed Ellipse