### Form Only / Form and Location Options

Form Only Profile: A Form Only list appears for profile FCF dimensions if you do not specify a datum for the dimension. Whenever this list appears it signifies that the dimension is a "form only" profile dimension. A form only profile dimension determines how close the profile dimension matches the same form as its nominal. Form only ignores whether or not the location of the profile is outside of acceptable tolerances. For a Form Only dimension, pay attention to the measured values in the generated dimension. Also, define the Best Fit Algorithm in the Profile area of the Advanced tab. See the "Advanced Tab" topic.

PC-DMIS 4.4 and later support the Form Only Profile of a Line when the considered feature is a constructed curve based on a linear scan. The theoretical points are projected onto the theoretical curve to determine what theoretical points and vectors to use in the profile calculation. Curves can also be used in the FCF per unit length profile of a Line.

Form and Location Line Profile: If you do choose a datum then a "form and location" profile is implied, and the Form Only list is replaced by the Composite check box, allowing you to determine whether or not the dimension is a composite line profile dimension. See "Composite check box" below. Form and location dimensions let you determine if a particular profile matches the same form and the same location as its nominal. This differs from the Form Only option, because the location of the profile must also be within acceptable tolerances defined by the Plus and Minus tolerances. For a form and location dimension, pay attention to Max / Min values in the generated dimension.

The Form Only list contains these two items:

- Single Segment - This is a single segment overall "form only" profile (as compared to a composite or two segment profile

- Per Unit - This behaves the same as the Per Unit check box for flatness except that for straightness and line profile, the "Per Unit" distance is a linear distance along a line (for straightness) or along a line, scan, curve, circle, or ellipse (for line profile). This item only applies to line profile, not surface profile.

Form and Location Line Profile: If you do choose a datum then a "form and location" profile is implied, and the Form Only list is replaced by the Composite check box, allowing you to determine whether or not the dimension is a composite line profile dimension. See "Composite check box" below. Form and location dimensions let you determine if a particular profile matches the same form and the same location as its nominal. This differs from the Form Only option, because the location of the profile must also be within acceptable tolerances defined by the Plus and Minus tolerances. For a form and location dimension, pay attention to Max / Min values in the generated dimension.

- A single segment "form and location" line profile: A double segment "form and location" line profile:

- A composite "form and location" line profile: