Edges
The system detects whether the edge is a
line, curve or arc, taking model accuracy into account and
displays the properties as set in the Measure Item
Customization dialog box.
Notes:

If the angle of an arc is less than
0.125 degrees, only the arc length is displayed in the
geometry area. The angle and radius are not displayed.

The system arbitrarily assigns end
points 1 and 2, however, once assigned, these points are
persistent. Note that the order of the point 1 and point
2 can be different whether you select an object in the
3D are or in the specification tree. The direction is
oriented from point 1 to point 2. Beside, the direction
vector is not reactive to the orientation of a line,
thus if you change the geometrical orientation for a
line (see picture below), the direction vector will not
be reversed.
Surfaces

Center of gravity:
The center of gravity of surfaces is visualized by
a point. In the case of non planar surfaces, the center
of gravity is attached to the surface over the minimum
distance.

Plane:
gives the equation of a planar face. The equation of a
plane is: Ax + By + Cz  D=0.
Note that there is an infinite number of
equations possible (and an infinite number of solutions for
values ABC and D). The result given by Measure Item does not
necessarily correspond to that in the feature specification.
This is because the measure is based on topology and does
not know the feature specification
associated with the measured item.
