On the Geometry ribbon tab, select the Add Beam by Perpendicular Intersection tool in the Beam group.
The mouse pointer changes to the Add Beams cursor ().
Click on any point along the first beam where the starting node of the new beam will lie.
A new beam member is "rubber banded" to this point.
Click on any point along the second beam where the end node of the new beam will lie.
A new node is created on the selected beam at the at the calculated perpendicular point and a the new beam member is added.
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