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etboards17
2010-09-01, 10:34 PM
I have scheduled many things, used shared parameters to control elements globally, and created area model take off spreadsheets comparing proposed and specified squarefootages within Revit. What I am trying to say is that I am dumbfounded on that fact that I cannot schedule that area of pads. What am I missing? Please laugh at me because I would love to be told how to do this :)

Alfredo Medina
2010-09-02, 03:15 PM
Assume you are in a view whose phase is set to new construction. Create a toposurface. Change its phase to Existing. Now use Graded Region, select "Create a toposurface exactly like the existing one" > Select the previous site. (This operation demolishes the existing site) Change the view to "Show new". Now create building pads on the new site. Then go to View > Schedule > Phase:new construction > Add the "Surface Area" field, and that gives you the area of the site and the area of the building pads, and the areas are correct.

That part is relatively easy. What is not easy to understand is how Revit calculates Cut and Fill volumes of the earth moved to create these pads. The volume values are always wrong, and not by a consistent percentage that at least I could calculate and fix with a formula. There are more examples of this at the following link: http://www.revitstore.com/index.php?option=com_content&view=article&id=128:revit-site-tools-cut-and-fill&catid=37:tips-and-tricks&Itemid=55

Can anybody please explain this issue?

etboards17
2010-09-02, 09:01 PM
Genius. I will post my experience and or questions.

Alfredo Medina
2010-09-08, 03:02 PM
...
That part is relatively easy. What is not easy to understand is how Revit calculates Cut and Fill volumes of the earth moved to create these pads. The volume values are always wrong, and not by a consistent percentage that at least I could calculate and fix with a formula. There are more examples of this at the following link: http://www.revitstore.com/index.php?option=com_content&view=article&id=128:revit-site-tools-cut-and-fill&catid=37:tips-and-tricks&Itemid=55

Can anybody please explain this issue?

Does anybody know what happens with Cut and Fill volumes? Can anybody get consistent results? There are more examples of this issue at the link provided above, with different sizes, all of them giving wrong results, but not even consistent. In my previous post, I posted an illustration. In this post, I am including a sample Revit file, if anybody wants to look at it. Thanks.

Gadget Man
2010-09-16, 12:24 AM
Does anybody know what happens with Cut and Fill volumes? Can anybody get consistent results?..

Alfredo,

Thanks for your message. I ran several experiments and came with pretty consistent results. I still have a discrepancy between Cut and Fill (they should be theoretically identical) but the difference is minimal and consistent.

By the way, in the calculations I used only the volume of the topography under the Pads. The PAD thickness in reality should be... 0. After all, what is a pad? It's only an area (two-dimentional = no thickness) for the building to be built on... Unfortunately, REVIT doesn't let you to have PAD of thickness 0, so the PAD volume should be included in the equasion - as a constant on both sides. Which doesn't change the above mentioned difference anyway...

See pictures below. The tests I ran were:

Fill = 1mm, Cut = 1mm, Fill volume = 0.085m³, Cut volume = 0.117m³, Difference = 0.032m³
Fill = 10mm, Cut = 10mm, Fill volume = 0.996m³, Cut volume = 1.028m³, Difference = 0.032m³
Fill = 100mm, Cut = 100mm, Fill volume = 10.101m³, Cut volume = 10.133m³, Difference = 0.032m³
Fill = 1000mm, Cut = 1000mm, Fill volume = 101.155m³, Cut volume = 101.188m³, Difference = 0.033m³
Fill = 10000mm, Cut = 10000mm, Fill volume = 1011.698m³, Cut volume = 1011.730m³, Difference = 0.032m³
Fill = 5000mm, Cut = 5000mm, Fill volume = 505.841m³, Cut volume = 505.873m³, Difference = 0.032m³
Fill = 273mm, Cut = 273mm, Fill volume = 27.604m³, Cut volume = 27.636m³, Difference = 0.032m³
Fill = 412.36mm, Cut = 412.36mm, Fill volume = 41.703m³, Cut volume = 41.735m³, Difference = 0.032m³So, as you can see, it doesn't matter really what the Cut and Fill values are (as long as they are identical) the CUT volume is virtually always 0.032m³ bigger...:shock: I'm almost inclined to think that it's due to a... compacting of the fill...;) But really, this is very interesting, because it is NOT percentage driven...

Alfredo Medina
2010-09-16, 02:01 AM
Jerry

Thank you very much! Very good analysis; well, at least it is good to know that the difference between Cut and Fill remained more or less constant in your experiments. It seems consistent when you look at the problem this way, comparing cut and fill. But it's the individual volumes what seems very weird, such as why a simple volume of 1m x 1m x 3m is not 3 cubic meters but something else? and the bigger the volume the bigger the error, but not by any constant percentage or factor? Well, yes, probably the programmers put some kind of waste factor that is random and impossible to detect. Go figure!

Thanks again. I very much appreciate your help on this matter.