Hello, We have similar issue ... Duct area (and furhtermore, the duct insolation area) is computed from duct accessories, in whose families are parameters of width/height/depth named at least by two ways (width or duct_width, height or duct_height, Length or L) and thus we have in sheet specification list more columns of more such parameters. Goal is to achieve computed values of area based on different named parameters (with same meaning) in just one column instead of more columns and this goal is simply destructed by the fact, that You cannot simply sum all the areas to one column. examine the equations for both kind of area : width*height=A1 and duct_width*duct_height and in final column i need value A1 + A2
thus in parameter made by formula may be prepared: (width*height)+(duct_width*duct_height).
But the grand problem is, that each result based on equation which is based on non-existing parameters, determines whole result as "non-existing" and it gives an empty cell.
Of course there is solution: create in each duct accessory parameters the "other" parameter which not exist there, and it raises value of parameter as number 0.0 .. but this is not what i want : to waste time by creating new unused parameters in dozens of families in my BIM model !
i want to just sum all possible values and the other non-existing result simply ignore with some rule :
if parameters on which is based the result not exists, simply do not account it to final result, or:
if parameter not exist (in particular family), then simply define it as 0 or 1 (according another rule) . this brings further to the computation A1 + A2 possible result, e.g.
256 + 0 = 256 (which is final desired result)
instead of
256 + null = null (which is not what we want)
It is a grand shame for Autodesk that in Revit software tool so sophisticated such Revit are such dumb bugs and such lack of functionality still exists !!! Now still i feel angry when need to eat hours of editing of families to update their parameters which simply could be avoided to implement higher logic with datamanagement within the schedule data !
simiral problem like in post here: Schedules quantitiy problem: Calculated Value = null + value