If you select the Remove outliers check box in the Construct Filter Feature dialog box (Insert | Feature | Constructed | Filter), PC-DMIS attempts to remove all points a given number of standard deviations from the substitute feature (usually a circle or a line). You specify the number of standard deviations in the Standard deviation multiple box. See the "Standard Deviation Multiple box".
Outlier removal behaves similar to filtering:
If you select the Linear option, outlier removal is based on the 3D distance from the point in question to the line (best fit line through the data).
If you select the Polar option, outlier removal occurs in the radial direction (parallel to the workplane).