When you create a material take off you can add a “Volume” parameter and a “Material:Volume” parameter.
The “Volume” parameter is reporting the volume of the complete family, the “Material: Volume” is reporting the volume per material used in the family.
But this is not exactly true…
Let’s look at the following example:
A simple family with 3 boxes: one with a volume of 1 m3, one with 0.5 m3 and one with 0.25 m3. All of them using the same material.
This means a total value of 1.75 m3.
But in the material take off in the project the “Volume” and “Material:Volume” are NOT 1.75 m3 and are also completely different:
The reason is that both of them are calculating the volume of the family objects for another detail level.
- “Volume”: will only calculate the volume of all objects on “Coarse” level.
- “Material:Volume” will only calculate the volume of all objects on “Fine” level.
- The volume of family objects that are on “Medium” level will never be calculated.
- Objects that are on “Coarse” AND “Fine” level will be calculated for “Volume” AND “Material:Volume”.
In my family the 1 m3 cube is only on “Coarse” level, the 0.5 m3 cube is only on “Medium” level and the 0.25 m3 cube is only on “Fine” level.
(To change the detail level of an object in a family: select the object and use “Visibility Settings”)
So now it makes sense.
“Volume” is only calculating the volume of the 1 m3 cube because only this object is, in the family, on “Coarse” level.
“Material:Volume” is only calculating the volume of the 0.25 m3 cube because its the only object on “Fine” level.
The 0.5 m3 cube in the middle is not used in volume calculation because it is on “Medium” level.
This is also the same for “Volume” calculation in regular “Schedule/Quantities” views.