For axial features, such as cylinders, you can specify where along the axis PC-DMIS should create the Position dimension. You can tell PC-DMIS to create the dimension at the axis' average (or centroid ), at the axis' start point, at the axis' end point, at the axis' worst end (the end with the greatest deviation), or at both ends of the axis. You can also create the dimension at a specified reference length away from the selected point on the axis.
To use the reference length with a Position dimension:
Type the desired value in the Reference Length box in the Position dialog box (Insert | Dimension | Position).
Select one of the option buttons (From Axis Average, From Start Point Of Axis, From End Point Of Axis, From Worst End Of Axis, or From Both Ends Of Axis).
Click the Create button. PC-DMIS locates the selected point (or points if you've selected From Both Ends Of Axis) and then moves along the axis the distance of the specified reference length and creates the dimension(s) there.
Reference
Length
The value in this box specifies the length from the selected point or axis
end where PC-DMIS will create the Position dimension.
From
Axis Average
This option tells PC-DMIS to dimension the axial feature, from the centroid
(or average) of the axis.
From
Start Point of Axis
This option tells PC-DMIS to dimension the axial feature from the Start
Point of the axis.
From
End Point of Axis
This option tells PC-DMIS to dimension the axial feature from the End Point
of the axis.
From
Worst End of Axis
This option tells PC-DMIS to dimension the axial feature from the start
or end point that gives the worst-case scenario for the dimension. PC-DMIS
creates the dimension at the axis end that deviates the farthest from
the nominal. For example if your part contains a skewed cylinder, the
start or end point along the cylinder's axis that deviates farthest from
the nominal is the point that gives the worst-case scenario.
From
Both Ends of Axis
This option tells PC-DMIS to dimension the axial feature, from both the
start and end point of the axis selected. PC-DMIS creates a dimension
at both ends of the axis.