How do I measure size (dimensions) of the geometry and/or sky sphere?

So I need to make sure SLS Capture size is appropriate and is smaller than bounds of my geometry that makes up my level. I can’t seem to find how to see the dimensions of the selected actors :confused: For example, in Radiant level editor, once you select something, it shows a bounding box with dimensions of that selected object(s).

How do I get to see the size (dimensions) of the selected geometry and/or sky sphere?