So from looking at mods others have made, I was able to reason how some of the perks work. For example, many perks can be altered by changing a single variable. The "night thief" perk is an example of such a perk. You just change the value in the EPFD subrecord to whatever you need it to be. I also determined that you can create a ranked perk by adding a NNAM subrecord that references the formID of the next perk in the rank. So all that stuff works fine for me.

However, I do have issues understanding one thing. Perks like the "Extra Pockets" perk reference a magic effect to apply their effects. But I don't see how the PERK record references the SPEL record. It seems that the only relation I can find is in the Editor ID. Most of the perks like this seem to be named in a particular way. In the case of extra pockets, the PERK record is called ExtraPockets and the SPEL record is called PerkExtraPockets.

Is this really how you link a PERK record to a SPEL record, or am I missing something?

It's linked via PRKE and DATA:

PRKE ( -------------------- Rank Effect Header --------------------)
Effect Type: 1 (Linked SPEL)
Rank Index: 0

DATA (Linked SPEL Record)
Form ID: 00096592: SPEL (PerkExtraPockets)

So for multi-level perks is that info defined only in the record of the last perk in the rank?
For example, in the haggling perk tree the only PERK record that has an entry like you posted is the highest ranked perk in the haggling line? How do they link the other perks to the corresponding spell effects?

Actually, these perks are type 2, complex. I guess the behave differently?

Yes, the function of DATA entries always depends on the previous entries

I think it would be easier to anolyze Fallout Perks, so we have something to compare

In this case it's

PRKE: Complex
DATA: Some flags
EPFT: Extra Data: Float
EPFD: 0.77

100% / 130% = 0.77

Sorry, I'm not sure I understand. When you say "DATA entries id always dependent on the previous entries" what do you mean exactly? Are you referring to this portion?
"EPFT: Extra Data: Float
EPFD: 0.77"

The value in EPFD is a Floating Point Number as defined in EPFT? I know haggling maxes at a 30% discount, but how do you determine what each rank does to the effect?

I don't have fallout, so I can't look at the perk structure there. Is there a maybe a reference site or wiki on the subject?
I've been using http://www.uesp.net/wiki/Tes5Mod:Mod_File_Format as my reference in my perk edits, but there is not data on the PERK records.

Sorry, I'm still figuring all this out. I appreciate you help.

The sub-records are dependent on each other

PRKE defines the type of the perk-effect
DATA contains the data that is required for that kind of perk effect, and for some types of PRKE there is additional Data
EPFT defines the type of the additional Data
EPFD is the actual additional data.


in "Haggling60" TESsnip just messes things up, and displays the float as hex:

EPFD = CD CC 4C 3F, that's the Hex notation of the floating point value 0.8 (100/125)

Same for the others:

40: E1 7A 54 3F = 0.83 (100 / 120)
20: 52 B8 5E 3F = 0.87 (100 / 115)


In the Editor the Perk Entry for Haggling80 will look like this:
http://jo-ge.net/dl/perk.png


As for testing: You could always download the Fallout3 Editor anyway and use it to anolyze a random Perk-Mod for Fallout3.
I'm also just trying to interprete the PERK entry right now, it's interesting, but will be utterly obsolete knowledge once the CK is released.

Ohhh, well that makes a lot more sense now.
Sorry, I had to leave for a bit. I got caught in a meeting. Thanks for the help. It's much clearer now.