For example, if an external brick wall is measured on a plan using the external perimeter line, and the internal gyprock wall is measured on the internal perimeter line, and those two lines are 100mm apart on the plan, a door or window opening will not effectively cross both shapes if the Opening Span is set to 80mm. Changing the span size will correct this.
To access the Opening Span option:
1. In the Job Manager window, click the Cubit Estimating application button.
2. Click Options.
Fig1. Cubit Estimating Options
3. Click Jobs tab and change Opening Span field.
Fig 2. Opening Span option
4. Click OK to apply the changes.