HD headscratcher

[The_Admiral]

What exactly does HD does in pc's
please i really dont know

[jindra34]

Practically any die roll that is directly added to your max HP. The xdy+zda+bdc... HD would be x+z+b.

[Serpentine]

Erm... Everything? "Class levels" is the PC name for "HD", basically. Then there's the various HD-specific spells, as referred to above...

[PhoenixRivers]

HD are used to determine the effects of some spells, as well as to determine character HP, and the like.

Generally, for PC's, class levels will each grant 1 hit die. Sometimes, players have characters with Racial HD as well, in which case, they grant benefits by creature type.

[The_Admiral]

Oh now that's been cleared up
Next question
What is RAW?
I have heared alot of people mention it but what does it stand for?

[Serpentine]

"Rules as Written"

[hamishspence]

Rules As Written- sometimes, the way a rule is phrased can lead to a very weird result- such as a creature with -8 hit points being reset to 0 hit points by dunking its head in water (drowning rules)

Following the rules exactly as written, no matter how odd the result, is "playing RAW"

[Yora]

It's Read As Written.

Opposed to Read as Intended.

Sometimes the rules regarding certain aspects of the game are written in a way that is not completely obvious to understand, or don't seem to make much sense as they are written. When anyone asks about RAW, he want's to now what the rule exactly says.
RAW often isn't the best way to handle something, as writers sometimes make mistakes. But you can only guess what the original writer intended a feat, spell, or ability to do, so it's common to talk about the rules RAW.
Because if you want to RAI, everyone can come up with different things.

[Eldan]

To comment more than that, generally, people differentiate between "Rules as written" and "Rules as intended" (RAI). Sometimes it becomes quite clear that the designer of the rules didn't think of effect or interaction that would be caused by the way they worded a spell, feat or other rule text, making things broken when they clearly weren't meant that way. Rules as intended is what people think the designer actually meant when he wrote it.

[Serpentine]

Aha. I always read "RAI" as "Rules As Interpreted". Same thing, really.

[Yora]

Which actually fits it better, as we have no idea what the writers intended.

[ericgrau]

HD ~= level. But it may include both racial HD (monstrous HD) and class level. Literally it's "hit die", the thing you roll for HP every level, but it actually includes everything else too.

"RAW" is often excessively literal, though I see no reason for it to be that way. Then comes "RAI" (rules as interpreted), or I like "RAMS" (rules as makes sense). I mean, RAI usually makes more sense than RAW, but then it opens the door for "Well, that's just your interpretation, I can drown myself up from the negatives into 0 HP dagnabbit!"