### Constructing an Offset Line

A line can be constructed a specified distance from the input features.

To construct an Offset Line:

1. Access the Construct Line dialog box (Insert | Feature | Constructed | Line).

2. Select the Offset option.

3. Select at least two features from which to create the offset line. They can be of any type.

4. Click the Offsets button. The Line Offsets dialog box will appear.

Line Offsets dialog box

5. Click the Calculate Noms option and enter the offset values for the desired features in the offset field or Click the Calculate Offsets option and change the nominal values (see the procedures below).

6. Click the OK button. The Line Offsets dialog box will close.

7. Click the Create button.

PC-DMIS will iterate and construct a line such that the shortest distance from each input feature to the line is the corresponding offset amount. PC-DMIS will make all offsets in a direction perpendicular to the given surface normal direction. PC-DMIS will apply negative offsets in the same general direction that the points are measured. Positive offset values will be applied opposite the probing direction. If there is no probing direction (i.e., the input points were constructed), PC-DMIS uses the current work plane to determine the general direction for applying the offsets. Positive offsets will be applied in the plus direction of the third axis of the current work plane. Negative offsets will be applied in the minus direction of the third axis of the current work plane.

Note: The sign (positive or negative) of the offset value, control on which side of the input features the line is constructed. If you get the opposite line than was expected, cancel the feature and reconstruct it, reversing the sign of the keyed in offsets. For example, if the offsets are 1.0, 2.5, 3.5, change them to -1.0, -2.5, -3.5.

The Edit window command line for this option would read:
CONSTR/LINE,OFFSET
SURFACE NORMAL = i_vec, j_vec, k_vec, TOG1
ID = id1, id2, …
OFFSET = val1, val2, …

Note: TOG1 = changes between MULTI POINT and TWO POINT. The TWO POINT algorithm is only available for parts created using PC-DMIS version 2.1 or earlier.

You can calculate the offset value in two ways:

- Changing the offset directly for the input feature of your choice, and then click the Calculate button to updating the nominal values.

- Change the nominal values for the selected feature, and then click the Calculate button to update the offset values.

These are described below.

More:

Changing Offsets Directly to Calculate Nominals

Example of Calculating Nominals

Changing Nominals Directly to Calculate Offsets

Example of Calculating Offsets