Is there any routine to get the amounts of parameters summed only from the selected elements? In autocad, the parameters window automatically sums the quantities as we select the lines, but in revit it is necessary to make a schedule, which takes a lot of time for a quick check.
Select Model Elements (or get current selection). Get parameter(s) value by name (or you could get all parameters, get data types, then filter parameters with a numeric value than can be summed). Sum.
You can try with this node GetSelectedElements : Class Selection | Open MEP