Prior to NX 11.0.1, when defining a Vector direction using the Face/Plane type, the selection is limited to a single selected object. This is problematic and can result in design errors if the reference object needs to be a group of faces, since only one face can be selected.
To illustrate the problem, let’s look at a command that employs a Vector block (i.e. Specify Vector UI in the dialog).
Say you want to define a Datum CSYS of type Axis-Axis-Origin where one of the axis direction is along a group of faces. When defining Face/Plane Normal for any of its defining axes as shown in Fig. A, the selection is limited to a single selected object.
Fig. B shows an example where a Datum CSYS feature is created with its origin point associated to an existing point-on-curve (orange sphere along the blue Intersection Curve feature curve), its Z-axis associated normal to the single selected face (orange face), and its X-axis along the work part’s X-axis.
So far all is in order. But if the user changes the existing point on curve location to somewhere else (shown in blue cross in Fig. C), the Z-axis normal direction at the relocated point is still referencing the originally selected face in Fig. B, thus the new Datum CSYS is not oriented correctly as intended as shown in Fig. C. See the problem? This could lead to design error if the said Datum CSYS is associatively used downstream in the design process.
In NX 11.0.1, the Vector definition is enhanced. When type is set to Face/Plane type the user is now able to select a chain of objects (e.g., tangent faces, body faces, etc.). Using the same exercise mentioned above, when defining the Z-axis reference vector, selection intent is available, Tangent Faces rule being the default. The user can select the chain of tangent faces (orange faces as shown in Fig. D) as the reference object.
This way, even if the user changes the existing point-on-curve location to somewhere else (shown in blue cross in Fig. E), since the Face/Plane Normal of the reference axis (Z-axis in this example) is associative to a chain of objects, the normal direction at the relocated point is adjusted accordingly with respect to the face on that new location. See result in Fig. E.