Click Stacked Dimensions
in the Annotations toolbar (Dimensions sub-toolbar).
Click a first point on the view.
Click a second point on the view.
You just created a first dimension within the stacked
dimension system.
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Click a third point on the view.
You now created a second stacked dimension in the system.
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Click a fourth point on the view.
You now created a third stacked dimension in the system.
Note that this stacked dimension is inserted properly into the system.
You can create as many stacked dimensions as desired.
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Click in the free space to end the stacked dimension
creation.