Skyrim Mod:Mod File Format/WTHR

WTHR records contain information on weather. Weather is essentially a group of static (relative to camera) clouds, a group of dynamic clouds, a sky model, maybe sound, and some other data tied together. Weather indoors is mostly lighting data.

Note: WTHR uses an unusual field type naming convention for the dynamic clouds, it starts with 00TX and goes to L0TX, but rather than just 0-9 A-L, it simply uses the sequential ASCII characters, so after 90TX is :0TX, ;0TX, etc. Rather than put all 20+ identical field combinations on the page, simply one *0TX field is listed.

C	SubRecord	Name	Type/Size	Info
+	EDID	editorId	zstring	Editor id
-	*0TX	cloud textures	zstring	Path to .dds - 00TX maps to layer 0, layer n will use a texture, if there's a field ascii(ord('0')+n)0TX
-	LNAM	unknown	uint32	Number of Texture Layers always 0x04 or 0x1d
-	MNAM	precipitation	formID	Precipitation - SPGD formID
-	NNAM	visual effect	formID	Visual Effect
-	RNAM	unknown	struct	32 bytes, Cloud Speed Y (-0.1 - 0.1), byte n corresponds to layer n, float encoded as uint8: 0x00->-0.1, 0x7f->0, 0xfe->0.1
-	QNAM	unknown	struct	32 bytes, Cloud Speed X (-0.1 - 0.1), byte n corresponds to layer n, encoding as above
+	PNAM	cloud texture color	struct[32]	512 bytes, 32 structs of 16 bytes, one for each layer rgb Sunrise rgb Day rgb Sunset rgb Night
-	JNAM	cloud texture alpha	struct[32]	512 bytes, 32 structs of 16 bytes, one for each layer float Sunrise alpha float Day alpha float Sunset alpha float Night alpha
+	NAM0	unknown	struct[]	208/224/272 bytes, structs of 16 bytes, color definitions rgb Sunrise rgb Day rgb Sunset rgb Night The n-th struct corresponds to the following type 0 - Sky-Upper 1 - Fog Near 2 - seems to be ignored, might correspond to "Cloud Layer" which is overwritten by more detailed PNAM field 3 - Ambient 4 - Sunlight 5 - Sun 6 - Stars 7 - Sky-Lower 8 - Horizon 9 - Effect Lightning 10 - Cloud LOD Diffuse 11 - Cloud LOD Ambient 12 - Fog Far defaults to black 13 - Sky Statics defaults to black 14 - Water Multiplier defaults to white (? see NAM2/3) 15 - Sun Glare defaults to white 16 - Moon Glare defaults to white
-	FNAM	unknown	struct	32 byte structure - Fog Distance float Day Near float Day Far float Night Near float Night Far float Day Pow float Night Pow float Day Max float Night Max
+	DATA	unknown	struct	19 byte structure - several uint8 are displayed as float by the CK, see the ranges given uint8 Wind Speed (0-1) uint8 unknown - always 0 uint8 unknown - always 0 uint8 Trans Delta (0-.25) uint8 Sun Glare (0-1) uint8 Sun Damage (0-1) uint8 Precipitation - Begin Fade In (0-1) uint8 Precipitation - End Fade Out (0-1) uint8 Thunder / Lightning - Begin Fade In (0-1) uint8 Thunder / Lightning - End Fade Out (0-1) uint8 Thunder / Lightning - Frequency 255 low to 15 high DefaultWeather has 0 here, displayed as low by the CK too uint8 flags - first four are Precipitation/Weather Classification (at most one set, defaults to None), following two are Effects/Aurora 0x01 - Pleasant 0x02 - Cloudy 0x04 - Rainy 0x08 - Snow 0x10 - Always Visible 0x20 - Follows Sun Position rbg Precipitation/Lightning Color uint8 unknown - always 0 uint8 Wind Direction (0-360) uint8 Wind Dir Range (0-180)
-	NAM1	unknown	uint32	Disabled flags - bit n corresponds to layer n, set if disabled
*	SNAM	ambient sounds	struct	8-byte struct formID - Sound Reference (SNDR) uint32 - Type 0 - Default 1 - Precip 2 - Wind 3 - Thunder
*	TNAM	sky statics	formID	Static (STAT) formID
-	IMSP	image spaces	formID[4]	Array of 4 (IMGS) formIDs (Sunrise/Day/Sunset/Night)
*	DALC	lighting data	struct	Directional Ambient, 4 fields for Sunrise, Day, Sunset, Night, usually 32 bytes, but just 24 in one case (TESTCloudyRain) rgb - Directional Ambient X+ rgb - Directional Ambient X- rgb - Directional Ambient Y+ rgb - Directional Ambient Y- rgb - Directional Ambient Z+ rgb - Directional Ambient Z- rgb - Specular Color defaults to 0/0/0 if absent float - Fresnel Power (0-1) defaults to 1 if absent
-	MODL	aurora model	MODL	Aurora - Includes optional field MODT
-	NAM2		uint32[4]?	unknown - appears together with NAM3, either four times 0x00ffffff or 0xffffffff, probably responsible for some of the default whites in NAM0. Only found in a couple of older forms, goes away when saving in CK.
-	NAM3		uint32[4]?	unknown - same as NAM2

The weather TESTCloudyRain contains the following alternative fields:

SubRecord	Type/Size	Info
DNAM	zstring	Cloud Texture Layer 0 - Alternative to 00TX
CNAM	zstring	Cloud Texture Layer 1 - Alternative to 10TX
ANAM	zstring	Cloud Texture Layer 2 - Alternative to 20TX
BNAM	zstring	Cloud Texture Layer 3 - Alternative to 30TX
ONAM	uint8[4]	Alternative to QNAM uint8 cloud speed layer 0 uint8 cloud speed layer 1 uint8 cloud speed layer 2 uint8 cloud speed layer 3 0x00 to 0x7f corresponds to CK displayed values of 0 to 0.1, unclear how values 0x80 to 0xff would be interpreted