EFF file format
FileExtension : EFF
Content : Description of effects files EFF V2.0
History : File done by IEFFHP
Update: Avenger (01.08.2003)
 
Description

The EFF file is an effect description. The size of an EFF file is (I believe) constant. The EFF format is to replace the old effect structs that appear in CRE, ITM, and SPL files. At least in CRE files, whether EFF V2.0 or the old structs appear is indicated by a flag in the header. Sorry, I don't have time right now to go into more detail, or to figure out exactly what is going on. 
EFF file (versions)

    * EFF V2.0: ToTSC, Icewind Dale, Baldur's Gate 2

EFF V2.0

Overall structure

    * Header
    * Body

EFF V2.0 Header
Offset Size (data type) Description
0x0000 4 (char array) Signature ('EFF ')
0x0004 4 (char array) Version ('V2.0')
EFF V2.0 Body
Offset Size (data type) Description
0x0000 4 (char array) For on disk effects, this is a copy of the Signature field from the header. For embedded EFF V2.0 structures, this is zeroed out.
0x0004 4 (char array) For on disk effects, this is a copy of the Version field from the header. For embedded EFF V2.0 structures, this is zeroed out.
0x0008 4 (dword) Effect type
0x000c 4 (dword) Target type
0x0010 4 (dword) Unknown
0x0014 4 (dword) NP1
0x0018 4 (dword) NP2
0x001c 4 (dword) Flags
0x0020 4 (dword) Time
0x0024 2 (word) Probability 1
0x0026 2 (word) Probability 2
0x0028 8 (resref) resource
0x0030 4 (dword) die sides
0x0034 4 (dword) dice count
0x0038 4 (dword) save type
0x003c 4 (dword) save bonus
0x0040 4 (dword) Is Variable? (same as 0x2c in EFF V1.0)
0x0044 4 (dword) Spell School
0x0048 4*3 (dword) Unknown
0x0054 4 (dword) Resistance Type
0x0058 4 (dword) NP3
0x005c 4 (dword) NP4
0x0060 4*2 (dword) unknown
0x0068 8 (resref) VVC
0x0070 8 (resref) 3. resource
0x0078 4 Center X position
0x007c 4 Center Y position
0x0080 4 Unknown X position
0x0084 4 Unknown Y position
0x0088 4 (dword) unknown
0x008c 8 (resref) Source of Effect
0x0094 4*3 (dword) unknown
0x00a0 32 (bytes) variable
0x00c0 4 (dword) caster level
0x00c4 4 (dword) unknown
0x00c8 4 (dword) Secondary Type
0x00cc 4*15 (dword) unknown
