Wall volume incorrect when Attaching Top

[Shaiki_]

I have 2 Identical solid concrete walls with a sloped top. When I attach top to a sloped reference plane, the volume is 164 cubic feet. When I edit the profile instead of attaching top, the volume is 245 cubic feet. Manual calculation says 245 cubic feet is correct. 

For calculating concrete volumes, this is obviously very bad. Attaching to reference planes is much better workflow-wise, so I want to know why that messes up the volume calculation. 

Can someone else test this and see if you have similar problems? I think it is only for sloped/gabled walls.

[barthbradley]

I can't replicate. I get the exact same volume either way.  Plus/minus 2% maybe - but 30% is an astronomical disparity.  There's got to be something else going on here.  

Following...

[Shaiki_]

I will attach a model with these samples. Maybe something going on behind the scenes. 

[barthbradley]

Nothing attached

[Shaiki_]

Attached is the file. The issue came up some time during the project, because it doesn't happen in a fresh project.

[barthbradley]

I don't readily see what the issue is with that one wall, but I can't replicate it even inside your own project.  I get 245.74 CF either way.    

[ToanDN]

Interesting. No answers at the moment.

[TripleM-Dev.net · Accepted solution]

Hi,

The placed walls have indeed a different volume (area is identical however...)

After some testing I found out the Reference plane is the issue (why??).

A new wall attached to the existing reference plane also reports the wrong volume.

Attaching the existing wall to a newly placed reference plane (over the old one) will report a correct volume.

Tested in Revit 2020.2.3

- Michel

[Shaiki_]

Thank you, that seems to work for me as well. Very confusing. I am also using Revit 2020.2 so maybe its something that got addressed in 2021.

Easy enough fix if its caught early enough...re-associating the reference plane does dissasociate some dimensions but overall, workable.  

[TripleM-Dev.net · Accepted solution]

Hi,

Nope, tried same file in Revit 2021 same result.

Would suggest sending the shared file to AutoDesk, this is clearly a 'Bug' and easy detectable, see if they can find the cause of it.

Also:

- Material takeoff is also wrong.

- Audit doesn't detect/fix it.

- moving the reference plane changes the volume, but remains wrong.

- a copy of the referenceplane also results in wrong volume, only a new reference plane solves it.

Also from the API data I can retrieve from the old vs new reference plane; I can't see a difference.

Only a reference to Tools4Revit for the wall instance, can't see how that would result in a different Volume.

- Michel

[Shaiki_]

Thank you for the thorough testing and investigation! I will try get ahold of Autodesk and see if it can be resolved.