I am a newbie, so please excuse if this is stupid, obvious, wrong or already a feature.
I often want to have a dimension that covers, say, the width of a room. But, somehow, for whatever reason, I have multiple line segments across the room. I’d like to be able to select multiple line segments with the dimension tool, and have the total of the selected line segments appear as the dimension. I can see the individual segment lengths, but don’t see a way to get the total.
The ‘Dimension’ tool not only works with individual edges, but also by selecting beginning and end of what you measure, Like @DaveR is demonstrating.
In fact beginning and end can also be midpoints of edges, intersections of: guides, guide with edge, guide with face or guide section plane. Or guidepoints.