Difference between revisions of "Talk:FA1C39F7"

Revision as of 16:12, 14 October 2010

Say What?

I`ve been investigating this record format because it is one of the most numerous formats in a lot file that I believe is corrupted. Unfortunately, I have been having some difficulty with the record format as described. Still, I have been able to decode nearly all of it. However, as my understanding of the record format has improved, I have discovered that the data I am seeing does not quite match the description. In the hope that someone could help me, and that my experience might help others, and not wanting to mess up the existing description with my misunderstandings, I documented my observations here. Even though my understanding of the format has improved considerably since originaly posting this commentary, and I have updated my description to match, I am still working on this record at the time of writing.

I start with some relatively simple structures that occur a variable number of times in the record, and build my way up towards the full description:

Anim blocks

• 16 Bytes: Unknown
• 7BITSTR: Unknown
• 7BITSTR: Unknown; apparently always "obj" or "int"
• 377 Bytes: Unknown, but some of the data patterns resemble CoOrdinate block data patterns.
• 7BITSTR: Unknown, but appears to always end in "_anim"
• 4 Bytes: Unknown, possibly DWORD?

Blend blocks

• 7BITSTR: Name
• 7BITSTR: Partner
• DWORD: Unknown; apparently always 0x00000000 or 0x3F7FFFB2

CoOrdinates blocks

• FLOAT: X
• FLOAT: Y
• FLOAT: Height
• 16 Bytes: Quaternion [Does anyone know how to "read" one of these?]

MaterialMesh blocks

• 7BITSTR: Material
• 7BITSTR: Mesh

Slot blocks

• 7BITSTR: Name
• CoOrdinates block

I call these blocks "Slot" blocks because some of the "Name" fields actually have the word "slot" as part of their value, and because the co-ordinates they contain often [if not always] make perfect sense as the object-relative locations of the object features mentioned in the correspoding "Name" field.

cObjectBlock blocks

• 7BITSTR: Unknown [Name?]
• DWORD: Unknown, only present for Version=17
• DWORD: Count
• MaterialMesh block: Repeat Count times

I had to invent a name for these blocks, but was singularly uninspired at the time. Any suggestions?

cObject blocks

• 7BITSTR: Model
• DWORD: Count
• cObjectBlock block: Repeat Count times
• CoOrdinates block
• DWORD: Count
• Slot block: Repeat Count times

cAnimatable blocks

• DWORD: BlockID; always the BlockID for cObject blocks
• DWORD: Version of embedded cObject block
• 7BITSTR: Name; always "cObject", matching the BlockID
• cObject block
• DWORD: Count
• Blend block: Repeat Count times
• Float: Unknown; always 1.0
• DWORD: Unknown; always 1
• CoOrdinates block: Occurs twice
• Unknown, 24 bytes long for Version<16, 28 bytes for Version>15; apparently cannot be a CoOrdinates block, not only because of the size, but because some values decode into "Not A Number"
• CoOrdinates block

cLocomotable blocks

• DWORD: BlockID; always the BlockID for cAnimatable blocks
• DWORD: Version of embedded cAnimatable block
• cAnimatable block

cPerson blocks

• DWORD: BlockID; always the BlockID for cLocomotable blocks
• DWORD: Version of embedded cLocomotable block

7BITSTR: Name; always "cLocomotable"

Full Record

• 64 BYTEs: Unknown, always zeroes
• DWORD: BlockID
• DWORD: Version
• 7BITSTR: Name; always matches BlockID
• cObject block: Only if BlockID matches cObject BlockID
• cAnimatable block: Only if Block ID matches cAnimatable BlockID
• cPerson block: Only if BlockID matches cPerson BlockID
• DWORD: Unknown, apparently always 0x00000000 or 0x00FE0000

Notes

The formerly inexplicably-varying portions of the record suspected to depend on the fields labeled "(Version?)" [as reported in the first version of this page] has been confirmed: the cAnimatable blocks actualy *do* contain cObject blocks, and the cPerson blocks also contain [or are always followed by] cLocomotable blocks, which contain [or are always followed by] cAnimatable blocks.

The cPerson and cLocomotable blocks seem to be singularly useless, apparently adding no significant information to the record.

The Anim block described on the main page has been observed sporadicaly, with no reliable means of programaticaly identifying their presence observed. In particular, its presence seems to bear no relation to the version number of any known part of the record. Further investigation is underway.

As part of that further investigation, I have used my tool to test-read EVERY lot in neighborhoods E001 and F001, neither of which has EVER been played, and begun scanning the lots in neighborhoods G001, N001, and N002, none of which has ever been played, and still have troubles with the data where the Anim block resides. At least one cPerson record has a Anim-block count of 3, followed by TWO Anim blocks and something that clearly is NOT an Anim block. Several other files have one or more of these non-Anim blocks at the end of one or more cPerson records, but so far I have only found the one record with such within the *counted* Anim blocks.

I still don`t know how to identify the presence of the Anim blocks by any way other than checking for the length of the unused data at the end of the record, but that method had proven absolutely reliable until that one abberant record was found. Incidentally, the record in question is Neighborhoods\G001\Lots\G001_Lot23.package, TypeID=0xFA1C39F7, GroupID=4294967295, InstanceID=218. --GeneralOperationsDirector