This is a warning message and not an error.

Circles, lines, and 2D widths are 2D features, and are not able to constrain the orientation sufficiently. They are not recommended as primary datums.

When you use a 2D feature as a primary datum, PC-DMIS levels to the view of the primary datum. In other words, the view becomes an implicit primary datum, and the specified primary datum becomes a secondary datum.

For more information, see "How PC-DMIS Solves and Uses Datums".

Case 1: As discussed in "How PC-DMIS Solves and Uses Datums", some feature types are 2D, and their workplane needs to be constrained higher-precedence datums.

Case 2: Sometimes this error occurs because a constructed 3D BFRE line was used as a secondary datum. It is very common for the THEO line vector of these lines to be non-parallel to the primary datum plane. This means that the nominal workplane of the line is not parallel to the primary datum plane, and so the primary datum plane does not constrain the workplane of the secondary datum line.

This error indicates that the considered feature doesn't have enough points for a unique fitted shape. For example, PC-DMIS cannot uniquely fit a cylinder with only four surface points.

Features with less than the absolute minimum number of points produce this error.

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The most common way to get this error is when the surface points of the feature are not placed in a way that constrain any degrees of freedom.

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You get this error when the geometric tolerance command cannot determine the degrees of freedom that are optimizable for the freeform considered features, subject to the datum reference frame.

To know those feature command types that are considered freeform, see the "Feature Types With and Without Surface Data" topic.

One of the ways you can get this error is if you don't measure enough of the full surface to help the geometric tolerance command understand the surface. Perhaps you only measured a single point on the surface, or only one cross section.

Another way you can get this error is when the nominal vectors of your measured points are not theoretically correct. For example, if you measure a plane, but the nominal vectors are not exactly planar. In this case, the geometric tolerance command thinks the surface isn't quite planar, but it won't be able to tell whether the surface is cylindrical, spherical, conical, or complex.

A third way you can get this error is when the nominal surface is almost symmetric in some way, but not quite. For example, perhaps it is almost planar, or almost cylindrical. In these cases, the geometric tolerance command cannot determine the optimal degrees of freedom.

Profile of a line tolerances have 2D considered features. Their workplane needs to be constrained by the datum reference frame.

Some tolerances, such as circularity of a cylinder, or the CIRCULAR_ELEMENTS local size interpretation, need their data to be measured in circular cross sections.

Several tolerances, such as perpendicularity, require at least one datum.

Multi-feature datums include datum patterns and common datums. They must all either have surface data or all lack surface data.

For information on feature command types that have and do not have surface data, see "Feature Types With and Without Surface Data".

Polar tolerances zones include radial-arc tolerance zones and perpendicular-to-radial tolerance zones. The considered features must be nominally parallel to the polar axis defined by the datum reference frame.

Polar tolerances zones include radial-arc tolerance zones and perpendicular-to-radial tolerance zones.

Polar tolerances zones include radial-arc tolerance zones and perpendicular-to-radial tolerance zones. They only make sense when the datum reference frame defines a clear polar axis.

Multi-feature datums include datum patterns and common datums. If the multi-feature datum does not have a material modifier, then the datum features must have surface data.

The most common cause of this error is incorrect THEO values in the considered features and/or datum features.

The most common cause of this error is incorrect THEO values in the considered features and/or datum features.

You get this error with planar tolerance zones on axial features such as cylinders, cones, and circles.

Specifically, when the datum reference frame doesn't constrain the orientation of the tolerance zone, the actual value is not well defined.

You get this error when all these conditions are met:

• You have multiple profile tolerances.

• No datums belong to a simultaneous tolerance command.

• The profile tolerances have different tolerance zone math types.

The geometric tolerance command does allow datums without a material modifier to follow datums that have a material modifier. However, the no-material-modifier datum must have surface data.

When there are multiple considered features, they must be identical, except for having different locations and orientations. So, for example, cylinders must be all inner or all outer, and they must all have the same nominal size.

This is a very unusual error. The most common way to get this error is with a simultaneous position and profile of a slot, notch, or ellipse:

• Position treats the feature as a circle without surface data.

• Profile treats the feature as a freeform feature with surface data.

The error occurs because the simultaneous tolerance needs to treat the same feature two different ways at the same time.

This error occurs if geometric tolerances in your simultaneous tolerance have different reference frames; or the datums in those tolerances are not identical, are out of order, or use different modifiers.

You get this error if you aren't using the correct geometric tolerances for the simultaneous tolerance.

Some tolerances, such as symmetry and concentricity, require that the tolerance zone is fully constrained by the datum reference frame.

There are many circumstances where the geometric tolerance command allows you to put a translation modifier on a datum where it does not make sense.

If your secondary or tertiary datum constrains no degrees of freedom, this error occurs. Most likely, this either means (a) your print is wrong, or (b) there is a mistake in your measurement routine.

If this error happens after migration, one of the common reasons for the error is due to improper use of 3D best fit constructed lines. For more information, see "3D Best Fit Constructed Lines" in "Migration from XactMeasure".

This error occurs when using a DEFAULT math option with too many points. It can happen due to the feature math option, the datum math option, or the tolerance zone math option. The cutoff for how many points is "too many" is several tens of thousands of points.

The geometric tolerance command allows customized ASME datum reference frames. This error occurs when the customization does not make sense mathematically. It is very common to make mistakes with customized DRFs, and that can result in this error.

As discussed in "Deriving the Toleranced Feature", several ISO geometric tolerances use the extracted median line as the toleranced feature. All circular cross sections must have at least 90 degrees of arc.

This error can also happen with straightness of an axis (either ASME or ISO). As discussed in the "Straightness" topic, straightness of an axis requires that you measure the surface data in circular cross sections. If any of the cross sections have less than 90 degrees of arc, PC-DMIS shows this error message.

If you change a feature's measurement strategy, or if you change the number of rows in the measurement strategy, the feature can get out of synchronization with its child features, until the feature has been executed.

As discussed in "Position", "Profile of a Line", and "Profile of a Surface", lower segments of composite tolerances have strict rules to govern their datum reference frame.