Basically, the rules concerning weapons and their sizes were changed as they were from D&D version 3.0 up to version 3.5. The version 3.0 rules were complex and hard to explain and to follow for builders, the new version rules should be much more understandable.
Point 1. There are 3 types of weapons.
For a given character, a weapon can fall into one of three categories: it can be a light weapon, a one-handed weapon, or a two-handed weapon. Roughly speaking, a light weapon is a small and very light weapon, a one-handed weapon is a small but heavier weapon, and a two-handed weapon is a weapon so big and heavy that you have to use your 2 hands to hold it. Weapons that are smaller than light are too small/light to use effectively in combat (think using a toothpick in battle), and weapons that are larger than two-handed are too big to use.
Let's say that you are a human in a human town checking the creation of a human blacksmith (or a gnome in a gnome town checking the creation of a gnome blacksmith, or an ogre in an ogre town checking the creation of an ogre blacksmith). Then, the three categories of weapons are the following ones.
- The light weapons are the very small and light weapons: daggers, light hammers, sickles, handaxes, short swords, saps, ...
- The one-handed weapons are the small but not so light weapons: clubs, morningstars, battleaxes, flails, longswords, rapiers, scimitars, warhammers, whips, ...
- The two-handed weapons are the larger weapons: spears, quarterstaves, falchions, greataxes, greatclubs, greatswords, guisarmes, halberds, scythes, ...
Two-handed weapons ... can only be held two-handed. That means that you cannot use a shield at the same time, for example; and that you can't hold a secondary weapon in your off hand. When you hit with a two-handed weapon, you deal damage computed as follows: the base damage of the weapon (e.g., 2d6 = two six-sided die for a greatsword) plus 1,5 times a bonus damage depending on your Strength, plus (perhaps) some magical bonuses.
One-handed weapons ... they are the "normal" weapons. You can hold them in one hand, which means that you can hold a secondary weapon in your off hand, or a shield. When you hit with a one-handed weapon, you deal damage computed as follows: the base damage of the weapon (e.g., 1d8 = one eight-sided dice for a longsword) plus some bonus damage depending on your Strength, plus (perhaps) some magical bonuses.
Light weapons ... they too can be held in one hand, but they have the additional property that they are "light" and easy to manipulate (so, it's easier to feint and do precise moves with them). For example, the dice roll to determine whether or not you hit your opponent with a weapon is generally based on your Strength (i.e., the higher your Strength, the more likely you are going to manage to "punch" through your opponent's armour). But, if you wield a light weapon and have the Weapon Finesse feat, you can use your Dexterity instead of your Strength (i.e., try to aim precisely and find a hole in the armour) ... but that is only possible with a light weapon (or other specific weapons like a rapier). Light weapons also make very good off-hand weapons for people who fight with two weapons ... if you use a light weapon in your off-hand, the penalties for fighting with two weapons are decreased substancially.
As mentionned above, weapons that are smaller than light, or bigger than 2-handed ... simply cannot be wielded effectively in combat. But why make smaller or bigger weapons then? Well ... that's pretty stupid to craft weapons too small or too large intentionnally ... but, as a human, you might not always get to find a human-made weapons (or, as a gnome, you might not always find gnome-made weapons ... or as an ogre, you might not always find ogre-made weapons).
Point 3. Weapons from other people/races.
Let's say you are a human visiting Golden Oak (a gnome area), where gnomes sell gnome-sized weapons. What then? Gnomes might make gnome-sized greatswords that they wield two-handed ... but if you, a human, wants to wield such a small-sized greatsword, you wouldn't need 2 hands, would you? What if you want to hold a gnome-sized dagger? Fret not ... here come the answers!
There are 3 weapon categories: light <-> one-handed <-> two-handed.
There are several size categories: tiny <-> small <-> medium <-> large <-> huge <-> ... and more
The rule is relatively simple and intuitive: If a weapon was made for a wielder that is one category smaller/bigger than you, then its type changes one category as well.
Let's examine the examples given above. The gnome-sized greatsword made by gnomes is a two-handed weapon for gnomes. But gnomes are small, one size category smaller than humans. So, for a human, this weapon won't be a two-handed weapon, but a one-handed weapon (one category smaller). And the human will be able to hold the gnome-sized greatsword in one hand only.
Does that mean that the human can hold two greatswords and thus make plenty of damage? Well ... no. Because the base damage inflicted by a weapon depends on its size too. A human-sized greatsword inflicts 2d6 damage (that's the base damage); but a gnome-sized greatsword does only 1d8 damage, because it's smaller. (Yes, life is tough for gnomes ... but they'll get other advantages sooner or later!) And a pixie-sized greatsword would do only 1d6 damage, because it's smaller than small (that is, tiny). So, in the end ... the human could well wield a gnome-sized greatsword in only one hand, but he wouldn't get any advantage from it: he might as well wield a human-sized longsword that way (you'll notice that a human-sized longsword does 1d8 base damage ... the same as a gnome-sized greatsword; that's because those two weapons are actually exactly the same: they differ in names only).
So, in all but names, we have: a human-sized (= medium) longsword = a gnome-sized (= small) greatsword = an ogre-sized (= large) shortsword. There's no way to "cheat the system".
And ... what about the gnome dagger then? Well, the gnome-sized (small) dagger is a light weapon for gnomes. For humans (one size category bigger), they would be "smaller than light". And, as such ... they can't be wielded.
Side remarks, and "to come" announcements.
- Most PC are size medium, but gnomes and halflings are size small. Centaurs and wemics are size large, and so are bugbears.
- Most weapon sizes have been changed so that they fit their expected wielder. That means that, as a human, you will most likely not be able to use a dagger built from a gnome shop. This is not a bug ...
- There might still be bugs though, but you have to think in terms of "expected wielders". If you fight kobolds and find out that you can't use their daggers (because kobolds are small), that's fine, and it's not a bug. If Mr Questgiver gives you a dagger as a reward for a quest and this dagger is small and you can't use it though, then it might be a bug. Such bugs should be sent to the builders address.
- The feat that allows character to wield oversized weapons (strong arm) has been removed from the game, and people who had bought it have been reimbursed.
- Dwarves, who recently went from Small to Medium, had some items automatically resized (including armours). If you have resized objects and find that they are wrongly sized for you, and think that ICly they should be your size, feel free to send a mail to the applications address or try to get the attention of an imm online (I'll try to be online tonight during the WD election test). But be reasonable: if it's a cheap object that you can simply buy again, then just buy it again (resizing is not that difficult, but it takes time).
- Same thing for non-dwarves who had renamed objects resized and can't set them back to the correct size.
- Dual-wielding warriors, and rangers in particular might see some nice free two-weapon fighting feats in the future ...
