topic Re: Rectangular vs Round Duct Dimensions in Revit MEP Forum

Rectangular vs Round Duct Dimensions

Anonymous — Mon, 25 Jul 2016 18:12:53 GMT

I'm trying to create a single parameter that will read the largest duct dimension (regardless of rectangular or round) in a duct schedule. Basically: Find the Greatest of Length, Width and Diameter, where some ducts have two of the three and some only have one.

So far, every time I've mixed round duct diameter based parameters with the rectangular duct dimension parameters, I get a blank box.

I'm trying to save time by not writing the same downstream formulas twice (once for round and once for rectangular ducts). I want it to work like the Hydraulic Diameter and Equivalent Diameter parameters.

Has anyone seen this before or gotten around it?

Thanks in advance!

Re: Rectangular vs Round Duct Dimensions

CADmonkey_UK_Building_Services — Tue, 26 Jul 2016 00:23:43 GMT

You need a Tag Family that reads the 'Size' property. This is common to round and rectangular duct. At the moment yours are reading width and depth or diameter.

Re: Rectangular vs Round Duct Dimensions

Anonymous — Tue, 26 Jul 2016 13:27:19 GMT

The Size parameter seems to have a whole new set of challenges for creating formulas. The rectangular ducts Size parameter is formatted as LxW and the round ducts Size parameters are Dø. Is there a way to strip those down to just numbers usable in a formula to find the largest value?

This is for a schedule, not just a tag.

Re: Rectangular vs Round Duct Dimensions

CADmonkey_UK_Building_Services — Tue, 26 Jul 2016 13:44:46 GMT

Try this with Schedule formalas::
1.Make a formula to derive the cross-sectional area from circular duct Diameter
2. Make another formula for Rectangular.Length & Width
3. Now you have the Surface Area the shape doesn't matter.

*edit* I may have just re-discovered the 'area' property.

Re: Rectangular vs Round Duct Dimensions

Anonymous — Tue, 26 Jul 2016 14:11:09 GMT

I'm after the largest duct dimension. Be it Length, Width or Diameter. Surface Area presents the same problem for combining the areas of round ducts into the same column as the areas of rectangular ducts.

I'm trying if(Diameter > 0, Diameter, if(Length > Width, Length, Width)). This returns a blank box for all rectangular ducts and the diameter of all the round ducts.

Is there another way to write this?

Re: Rectangular vs Round Duct Dimensions

Anonymous — Tue, 26 Jul 2016 14:46:59 GMT

I solved it.

Thanks for responses.

Re: Rectangular vs Round Duct Dimensions

mastjaso — Thu, 19 Jul 2018 18:37:50 GMT

Care to share said solution?