Size Category

A creature's size is classified in categories which represent an exponential ratio, as to keep the same ratio of size and effects on mechanics based on Size Difference instead of accounting sizes as absolute values.

The baseline of Size in AdVarTa is, by default, the mass, with some special cases, of course. An increase of 1 Size Category means that the mass/weight is doubled; an increase of 2 means that the mass/weight is quadrupled; an increase of 3 means that it's multiplied by 8 and so on. As for linear dimensions, they are doubled every 3 steps towards increasing Size Category, so, each +1 SC amounts to a new height/length of 2^(1/3) the original. For short, it can be rounded to either a 25% increase in height, or, to be more precise in the approximation, an increase of 26%.

As for special cases or exceptions to the categorization of Size according to mass, sometimes, different anatomies or composition of a creature can account for an increased or diminished mass which would normally account for a higher/lower Size Category, like the case of a golem of stone or steel, which might be heavier than an equivalent-sized humanoid, or a flying bird, which very often are considerably lighter than other animals of their size. In such a case, the go-to is simply considering some modifier.

Overall, the Size Category for an average human is proposed to be 0 (zero) and each step towards a bigger size doesn't necessarily have to be through doubling, quadrupling, etc. It's encouraged that Categories are defined as value ranges, like the following table, for example: In this given example table, normally a person X of 110kg is expected to be Size Category +1, just like a person Y who is 2,00m tall. However, it's encouraged to consider cases when they are still quite proportional to a previous category, like the SC 0 in the given table. Following this further example, the person X could be just a strong and stout individual, with 1,80m; while the person Y could be just a tall, slim person with some 80kg of mass. As such, wouldn't be healthy for the game to classify them as Size Category +1. As always with any ruleset, use common sense and good judgement to apply the rules.