About Quantities
Simplebim calculates quantities based on the geometry of objects. Because of this it doesn’t matter which model author tool was used for creating the models or who made them. Simplebim always calculates the quantities with the same logic in a consistent way. Thus quantities are comparable between different models and even between different projects. In other words Simplebim calculates standardized quantities.
Quantities are calculated both for object instances and container objects. For example a wall can either be an instance with single geometry or it can be an assembly with several child objects, which each have their own geometry and thus also their own quantities.
Geometry based quantities can be calculated with different kind of techniques. Which one is the best for you depends of course on your use case. This document categorizes the quantities based on the technique used for calculating them. Each category lists the object classes that the quantity in question is currently calculated for.