Circles for Diameters

[Underspec]

LEAST_SQR
MAX_INSC
MIN_CIRCSC
MIN_SEP
FIXED_RAD

The PCDMIS manual does not explain these in depth. I would like someone to explain a little more. I would also like to know what you guys think is the best for a hole diameter and for a stud diameter.


Thanks.

[JamesMannes]

This is from the help files...

LEAST_SQR
Least Squares ?This calculation type provides a method of fitting in which the average squared radial distance from the data points to the circle is minimized. The square root of this quantity is the Root Mean Square (RMS) distance. Since the RMS distance is based on an average, some points may be further than the RMS distance from the computed circle.
MIN_SEP
Minimum Separation ?This calculation type generates a circle that is halfway between two concentric circles containing the data points, with the difference of their radii as small as possible. The Min/Max math used by the MIN_SEP calculation minimizes the maximum error, or deviation, from the input data to the circle. The Min/Max error is one-half of the minimal separation. No input data points (or input features) lie farther than the Min/Max error from the Min/Max circle. This calculation determines whether or not all the input data (or input features) are within the given tolerances.
MAX_INSC
Maximum Inscribed ?This calculation type generates an empty circle with the largest possible diameter that lies within the data. PC-DMIS first computes a Minimum Circumscribed circle and requires that the center of the Maximum Inscribed circle lies within it. This option could be used for a circular feature that requires a mating stud. For example, if the input data represents a hole, then this calculation returns a circle with the diameter of the largest stud that will fit inside the hole.
MIN_CIRCSC
Minimum Circumscribed ?This calculation type generates a circle with the smallest possible diameter that encloses the input data (or input features). This option could be used when measuring a stud that would fit into a mating circular feature. The resulting feature would be the smallest hole into which the stud would fit.
FIXED_RAD
Fixed Radius ?This calculation type creates a circle of a given diameter, positioned so that the maximal radial distance from the data points to the circle is minimized. It is similar to the Max/Min math used in the MIN_SEP calculation except that,since the diameter is known in advance, the radius cannot vary. Only the circle's position is allowed to vary.

I use max inscribed for an i.d. and min circumcised for o.d.

[Underspec]

Does roundness change with these settings?

[Mike N.]

Does roundness change with these settings?

the roundness is independant of the type of filter used to calculate diameter