Skyrim Mod:Mod File Format/REGN

REGN are "regions", but not in the locational sense (those are LCTN). Each region ties together ambient information (weather/music/etc), presumably so they can be dropped into settings and provide a complete ambience.

Between the thick line are repeatable field sets, RPLI/RPLD come in pairs, and every occurrence of the bottom fields is preceded by an RDAT (sole exception: RDM0/RDSA can be under same RDAT). RDAT can also appear by itself (though rare).

C	V	Field	Name	Type/Size	Info
+		EDID	Editor ID	zstring
+		RCLR	region color	rgb	Map Color (unknown where used)
-		WNAM	world name	formid	World (WRLD).
-		RPLI		uint32	Edge Fall-off (World Units)
-		RPLD	data for "pl"?	struct[]	series of 8-byte structs, vary in length from 32 to 172 look like floats, coords?
-		RDAT	data header?	struct	8-byte struct uint32 Tab in CK 0x02 - Objects 0x03 - Weather 0x04 - Map 0x05 - Landscape (CK will save but not show data entered here) 0x06 - Grass 0x07 - Sound uint8 Flags 0x01 - Override uint8 Priority uint16 always 0
-		RDMO	music	formid	Music (MUSC) formid. Can appear with RDSA under same RDAT or on its own.
-		RDSA	sound data	struct[]	12-byte struct, total count arbitrary formid - Sound Reference (SNDR) uint32 - Flags 0x01 - Pleasant 0x02 - Cloudy 0x04 - Rainy 0x08 - Snowy float - Chance
-		RDWT	weather data	struct[]	12-byte struct, total count arbitrary formid - Weather (WTHR) uint32 - percent chance (all should add up to 100) formid - Global (GLOB, not used)
-		RDOT	Region generator objects	struct[]	Used for region generation: always 0 length in game files. 52-byte struct, total count arbitrary. formid - object to be placed int16 - Parent Index (-1 for none) (2-bytes) - Unknown float - Density uint8 - Clustering uint8 - Min Slope (degrees) uint8 - Max Slope (degrees) uint8 - Flags 0x01 - Conform to slope 0x02 - Paint Vertices 0x04 - Size Variance +/- 0x08 - x +/- 0x10 - y +/- 0x20 - z +/- 0x40 - Tree 0x80 - Huge Rock uint16 - Radius wrt Parent uint16 - Radius float - Min Height float - Max Height float - Sink float - Sink Variance float - Size Variance int16 x 3 - Angle Variance. x y z values: -180 to 180 (2-bytes) - Unknown (3-bytes) - Vertex shading color RGB uint8 - Shading radius ( 0 - 200) % objects - vertex shading extent as % of object radius textures - texture radius extent as % of parent object radius
-		ICON	shader?	zstring	path to .dds Trees\CanopyShadow.dds
-		RDMP	Region Name?	lstring	Map Name