Skyrim Mod:Mod File Format/CELL

CELL forms describe cells.

Record header flags:

0x00000400 - Persistent Cell?

0x00020000 - Off Limits

0x00080000 - Can't Wait

C	Field	Type	Info
-	EDID	zstring	Cell editor ID
-	FULL	lstring	In game name of the cell. Only in interior cells.
+	DATA	uint16	flags - Sometimes the field is only one byte long 0x0001 - Interior 0x0002 - Has Water 0x0004 - not Can't Travel From Here - only valid for interior cells 0x0008 - No LOD Water 0x0020 - Public Area 0x0040 - Hand Changed 0x0080 - Show Sky 0x0100 - Use Sky Lighting
-	XCLC	struct	(X, Y) grid location of the cell followed by flags. Always in exterior cells and never in interior cells. int32 - X int32 - Y uint32 - flags (high bits look random) 0x1 - Force Hide Land Quad 1 0x2 - Force Hide Land Quad 2 0x4 - Force Hide Land Quad 3 0x8 - Force Hide Land Quad 4
-	XCLL	struct	92 byte structure - Lighting rgb Ambient rgb Directional rgb Fog Near float Fog Near float Fog Far int Rotation XY int Rotation Z float Directional Fade float Fog Clip Dist float Fog Pow rgb Ambient X+ rgb Ambient X- rgb Ambient Y+ rgb Ambient Y- rgb Ambient Z+ rgb Ambient Z- rgb Specular Color? not shown in CK - assumed from LGTM float Fresnel Power? not shown in CK, usually 1 - assumed from LGTM rgb Fog Far float Fog Max float Light Fade Distances Start float Light Fade Distances End uint32 Inherit flags - controls which parts are inherited from Lighting Template 0x0001 - Ambient Color 0x0002 - Directional Color 0x0004 - Fog Color 0x0008 - Fog Near 0x0010 - Fog Far 0x0020 - Directional Rot 0x0040 - Directional Fade 0x0080 - Clip Distance 0x0100 - Fog Power 0x0200 - Fog Max 0x0400 - Light Fade Distances this field has only 64 bytes in NavMeshGenCellDUPLICATE001
-	TVDT	684 bytes
-	MHDT	1028 bytes
-	XCGD	struct	Only found in Xbox360 and PS3 official DLC, not supported by CK 1.8.151.0. uint32 - Count of substructures? Seems plausible, but doesn't always seem to match up. uint32 - String length, including null-terminator (like bzstring, but with a uint32 length) char[String length] - File name (looks to always be .nif files) ? - Other data here, but unclear what it is or what delineates the next file.
+	LTMP	formID	The lighting template for this cell.
-	LNAM	4 bytes
+	XCLW	float	Non-ocean water-height in cell, is used for rivers, ponds etc., ocean-water is globally defined elsewhere. 0x7F7FFFFF reserved as ID for "no water present", it is also the maximum positive float. 0x4F7FFFC9 is a bug in the CK, this is the maximum unsigned integer 2^32-1 cast to a float and means the same as above 0xCF000000 could be a bug as well, this is the maximum signed negative integer -2^31 cast to a float
-	XNAM	1 byte
-	XCLR	formID[]	Regions containing the cell (assumed from Oblivion).
Fields below this line can appear in any order.
-	XLCN	formID	The location for (of?) this cell.
-	XWCS	uint32	Size of XWCU/16 - CK changes this into use of XWCN Always has the value three in Skyrim.esm.
-	XWCN	uint32	Size of XWCU/16 Only one occurrence - 0x04
-	XWCU	struct[]	Water Current, series of 16 byte structures, minimum 3 float X float Y float Z float? unknown Unclear how structures are matched up to "Linear Velocity" and "Angular Velocity" shown in CK
-	XCWT	formID	The water for (of?) this cell.
-	XOWN	formID	Owner NPC or Faction (assumed from Oblivion). Only in interior cells.
-	XILL	formID	ID of an NPC_ or FLST. Only in interior cells.
-	XWEM	zstring	Water Environment Map only interior cells
-	XCCM	formID	Climate if interior cell behaves like exterior cell (assumed from Oblivion). Only in interior cells.
-	XCAS	formID	The acoustic space for this cell.
-	XEZN	formID	A reference to an encounter zone.
-	XCMO	formID	The music type for this cell.
-	XCIM	formID	The image space for this cell.

The last four bytes in XCLC do not appear to be a form ID. The following values appear 100 or more times in those last four bytes:

Count	Value
100	53bd00
279	53ba00
360	53d400
586	0
586	53d200
5881	53fd00
8397	53d100

The less frequent values show a distribution of values that makes them look like a bitmap.