One of the biggest challenges in Revit is quantification. It is known that we only get out of the model, what we have put before as an object in the model. Wow, great theorem…
Now, maybe next hint can help you to understand Revit when it calculates the volumes of your structural elements.
For custom families, Revit uses the Medium Detail Level presentation to calculate it’s object volume.
This representation can be set in the Family Editor, by selecting the solid geometry and change it’s Visibility/Graphics Overrides parameter. Only the solid(s) which have at least the “Medium” option checked, will be taken into account in the objects volume calculation.
This informative parameter “Volume” is often used in schedules of Structural Columns, Structural Framing, … and medium detail level is often used for simplified representation of your model. This leads us to next “problematic” combination.
Example 1 – Concrete column with corbels
Imagine this column with corbels. When wanting to look at just structural volumes, you can switch off the corbels, by changing to Medium Detail level, but in that means that the object volume does only takes into account the core of the column.
(Volume = 0,3 x 0,3 x 3 = 0,27 m³)
Example 2 – H-Wide Flange column
The default H-Wide Flange columns in the Revit content libraries by Autodesk works on the same principle. Medium detail level gives us simplified representation without filleted corners. But also this principle influences the objects volume.
Instead of using object volumes in your “Schedules”, create “Material Takeoffs” and use the “Material: Volume” parameter. This will take the full solid geometry that is consumed by the material into account, which gives us exact values for quantification.