"guess quantity" calculates the quantity with generic formulas and the formula is chosen based on the quantity name
"calculate quantity" calculates the quantity with a defined formula, different for every entity and quantity. The mapped formulas are specified here.
"Guess quantity" function is there from the beginning and it was a useful and fast way to suggest the quantity value to the user while "calculate quantity" was introduced after and it is, generally speaking, more precise because it uses a different formula for every entity and quantity.
Sometimes the two functions return the same value (for example with basic quantities like length) but sometimes they don't (for example with gross volume and net volume).
Keep in mind, btw, that they are tools that helps the user to specify the quantity but, in general, the quantity measure method depends by various factor and maybe, the used one, is not suitable for the purpose...so i suggest you to always check if the calculated quantities are what you expect.
Sooner or later as the calculate quantity feature matures, we should remove the guess quantity (or move into another system where perhaps we have a big list of "quantity algorithms" that the user can pick from).
Quantification is always a bit of a tricky topic, we need a way for people to create their own take-off rules (e.g. when considering the volume of a slab, any penetrations less than X m2 are not considered here in Australia (or something like that, I have to check with an actual cost planner ... but long story short there are all sorts of "gotchas" that are based off 2D paper-based take-off but are still used in the 3D world because benchmarks are based of those numbers).
Comments
"Guess quantity" function is there from the beginning and it was a useful and fast way to suggest the quantity value to the user while "calculate quantity" was introduced after and it is, generally speaking, more precise because it uses a different formula for every entity and quantity.
Sometimes the two functions return the same value (for example with basic quantities like length) but sometimes they don't (for example with gross volume and net volume).
Keep in mind, btw, that they are tools that helps the user to specify the quantity but, in general, the quantity measure method depends by various factor and maybe, the used one, is not suitable for the purpose...so i suggest you to always check if the calculated quantities are what you expect.
Sooner or later as the calculate quantity feature matures, we should remove the guess quantity (or move into another system where perhaps we have a big list of "quantity algorithms" that the user can pick from).
Quantification is always a bit of a tricky topic, we need a way for people to create their own take-off rules (e.g. when considering the volume of a slab, any penetrations less than X m2 are not considered here in Australia (or something like that, I have to check with an actual cost planner ... but long story short there are all sorts of "gotchas" that are based off 2D paper-based take-off but are still used in the 3D world because benchmarks are based of those numbers).
An expression builder like MS Access would be a dream. :)
Two columns: allowed functions and allowed parameters