Use the Define Gaps dialog box to define gaps in material lists where material volumes should not be calculated.
Access this dialog box from the Material List tab of the Sample Line Group Properties dialog box. Click the button in the Gap column for the 
Material List name.
- Add A New Gap
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Adds an entry to the List Of Gaps. After clicking this button, enter the start station, end station, and description for the gap.
Note: You can define Run Out and Run In distances for the gaps and choose to apply or not apply a gap in the Apply Gaps dialog box. - Delete Selected Gap
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Deletes the selected gap definition. Deleting a gap definition removes the gap type from all materials in the material list.