Issues with Project units & scheduling

[max.a.hollander]

I am running in to some issues regarding project units and the scheduling aspect of revit.

I have set my project units to round to .25 of an inch for detailing and creating accurate shop drawings. Once I set my project units to the precision that I am comfortable with everything is working fine until I Schedule ducts.  In construction we will order our duct work of a certain size , say 20 x 20 duct, in 4 feet increments.  I have detailed this on my show drawings and I have created a material take off schedule.  The issue that I am running in to is that even though my project units are set correctly Revit is telling that several pieces of duct are different regardless that the length and the size are the same.  Under further investigation I realize that in fact the duct is .001, or less, off from one another and thus being counted as different pieces.  I know that this is an easy enough issue to fix by moving the small amount to have them counted correctly.  Is there a way to have revit just realize that though the lengths may be off by a insignificant margin the ducts should be counted as the same?

[CoreyDaun]

Instead of sorting the Schedule by the Length Parameter, create a new "Rounded Length" Calculated Value. Create this as a Length Type with the formula:

round(Length/0.25")*0.25"

This formula will round the Length Value to the nearest 1/4", as per this example.

Length = 8.25817",  8.25817" / 0.25" = 33.03268,  rounded = 33,  33 * 0.25" = 8.25"

[max.a.hollander]

then i just hide the length parameter and rename rounded length to length?

[CoreyDaun]

Or just hide the Calculated Value. It doesn't really matter which one you hide since they'll both have the same "apparent" value.

[max.a.hollander]

why do you have to neutralize the units in this formula?  why doesnt just round(length) work? since your dividing by .25" then multiplying .25"

[CoreyDaun]

The ROUND function seems to only work with unitless Number values (not Lengths or Angles) so the units have to be stripped and re-applied. (My first post will be edited to include the inch symbol, which was inadvertently omitted.)

[max.a.hollander]

Gotcha.. What progaming convention dictates revit in this way is it C++ or something else.  the root of this inquary is where can i find a manuel with all of these strange work arounds.  Or is it best to ask forums and hopefully get answered quickly.  and as always CADastrophe (iif thats your real name) thank you for your swift response.