### Constructing a Best Fit or Best Fit Recompensate Sphere

A "best fit" sphere can be constructed using five or more features. 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 sphere, one for which PC-DMIS minimizes the average squared distance from the data points to the sphere.

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

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

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

3. Select five or more features.

Note: On Best Fit Recompensate, one of the five features must be a point.

4. Click the Create button.

The Edit window command line for this option would read:
CONSTR/SPHERE,BF,feat_1,feat_2,feat_3,feat_4,feat_5...
(Uses the actual measured points for construction.)
or
CONSTR/SPHERE,BFRE,feat_1,feat_2,feat_3,feat_4,feat_5...
(Uses the center of the probe for measurement.)

Constructing a Sphere from five or More Points | A - Best fit sphere constructed from five points.