===============================================================================
Universal Doom Map Format ZDoom extensions v1.33 15.09.2023


    Copyright (c) 2008 Christoph Oelckers.
    Permission is granted to copy, distribute and/or modify this document
    under the terms of the GNU Free Documentation License, Version 1.2
    or any later version published by the Free Software Foundation;
    with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
    
===============================================================================

This document discusses only the additions ZDoom makes to the UDMF 
specification.

=======================================
I. Grammar / Syntax
=======================================

    No changes.

=======================================
II. Implementation Semantics
=======================================

------------------------------------
II.A : Storage and Retrieval of Data
------------------------------------

Any TEXTMAP lump in the described namespaces must be encoded in either ISO 8859-1, Windows-1252 or UTF-8
with UTF-8 being the recommended encoding.

-----------------------------------
II.B : Storage Within Archive Files
-----------------------------------

In addition to the base specification ZDoom recognizes the following lumps
between the TEXTMAP and ENDMAP lumps:

    BEHAVIOR = contains compiled ACS code
    DIALOGUE = contains compiled Strife or USDF conversation scripts.
    ZNODES = Nodes (must be stored as extended GL nodes. Compression is allowed
                    but deprecated for portability reasons.)
    BLOCKMAP = blockmap. It is recommended not to include this lump in UDMF maps.
    REJECT = reject table. Recommended use is for special effects only.
    
    Lumps starting with 'SCRIPT' are guaranteed to be ignored by ZDoom so they
    can be used to store ACS and dialogue script sources.
    
--------------------------------
II.C : Implementation Dependence
--------------------------------

ZDoom supports all namespaces defined in the base specification and adds two new
ones:
    "ZDoom"
    "ZDoomTranslated"
    
The only difference between these two namespaces is how line, thing and sector
specials are handled:

'ZDoom' uses Hexen type specials which are ZDoom's native implementation.

'ZDoomTranslated' uses Doom-type specials. Such maps have to be processed by
a special translator. A special translator is a text lump that defines how
Doom-format specials are translated into Hexen-format specials. By default
each game defines its own translation table but these can be overridden in
MAPINFO. It is the mapper's responsibility to choose the correct translation
table for a map.


=======================================
III. Standardized Fields
=======================================

ZDoom's namespaces implement all fields from the standard, regardless of
any restrictions mentioned in the spec.
In particular, the 'ZDoomTranslated' namespaces implements thing specials.
These will ignore the implicit trigger type and triggering semantics are the
same as for native maps.
The only field not fully supported is the thing's 'friend' field. ZDoom does
not offer MBF's friendly monster implementation and will remap any use of this
field to 'strifeally', even for the 'Doom' namespace.

In addition to the standard fields, ZDoom defines the following:
Note: All <bool> fields default to false unless mentioned otherwise.

   vertex
   {
      zfloor = <float>;         // Floor height at this vertex. Only applies to triangular sectors
      zceiling = <float>;       // Ceiling height at this vertex. Only applies to triangular sectors
   }

   linedef
   {
      alpha = <float>;            // Translucency of this line, default is 1.0
      renderstyle = <string>;     // Render style, can be "translucent" or "add",
                                  // default is "translucent".
      playeruseback = <bool> ;    // New SPAC flag, true = player can use from back side.
      anycross = <bool>;          // New SPAC flag, true = any non-projectile 
                                  // crossing will trigger this line
      monsteractivate = <bool>;   // Monsters can trigger this line.
                                  // For compatibility only because this flag's 
                                  // semantics can not be fully reproduced with
                                  // explicit trigger flags.
      blockplayers = <bool>;      // Line blocks players' movement.
      blockeverything = <bool>;   // Line blocks everything.
      firstsideonly = <bool>;     // Line can only be triggered from the front side.
      zoneboundary = <bool>;      // Line is a boundary for sound reverb zones.
      clipmidtex = <bool>;        // Line's mid textures are clipped to floor and ceiling.
      wrapmidtex = <bool>;        // Line's mid textures are wrapped.
      midtex3d = <bool>;          // Actors can walk on mid texture.
      midtex3dimpassible = <bool>;// Used in conjuction with midtex3d - causes the mid
                                  // texture to behave like an impassable line (projectiles
                                  // pass through it).
      checkswitchrange = <bool>;  // Switches can only be activated when vertically reachable.
      walking = <bool>;           // Crossing activation checks if creature is on the ground, and fails if they are not.
      blockprojectiles = <bool>;  // Line blocks all projectiles
      blockuse = <bool>;          // Line blocks all use actions
      blocksight = <bool>;        // Line blocks monster line of sight
      blockhitscan = <bool>;      // Line blocks hitscan attacks
      blockfloaters = <bool>;     // Line blocks floating monsters' movement.
      blocklandmonsters = <bool>; // Line blocks walking monsters' movement.
      locknumber = <int>;         // Line special is locked
      arg0str = <string>;         // Alternate string-based version of arg0
      arg1str = <string>;         // Alternate string-based version of arg1
      moreids = <string>;         // Additional line IDs, specified as a space separated list of numbers (e.g. "2 666 1003 4505")

      transparent   = <bool>;     // true = line is a Strife transparent line (alpha 0.25)

      automapstyle = <integer>;   // Explicit automap style. Possible values can be
                                  //  0: Automap style is based on line properties (default).
                                  //  1: One-sided wall.
                                  //  2: Two-sided wall.
                                  //  3: Floor levels of front and back sectors are different.
                                  //  4: Ceiling levels of front and back sectors are different.
                                  //  5: 3D floor border.
                                  //  6: Wall with special non-door action.
                                  //  7: Secret door.
                                  //  8: Wall not seen yet.
                                  //  9: Locked door.
                                  // 10: Intra-level teleporter.
                                  // 11: Inter-level or game-ending teleporter.
                                  // 12: Unexplored secret wall.
                                  // 13: Portal line.
      revealed = <bool>;          // true = line is initially visible on automap.
      noskywalls = <bool>;        // true = skies are not drawn above or below this line
      drawfullheight = <bool>;    // true = draw the maximum height instead of the minimum height

      health = <int>;             // Amount of hitpoints for this line.
      healthgroup = <int>;        // ID of destructible object to synchronize hitpoints (optional, default is 0)
      damagespecial = <bool>;     // This line will call special if having health>0 and receiving damage
      deathspecial = <bool>;      // This line will call special if health was reduced to 0

      * Note about arg0str

      For lines with ACS specials (80-86 and 226), if arg0str is present and non-null, it
      will be used as the name of the script to execute, and arg0 will be ignored.

      lm_sampledist = <int>;         // lightmap customizable sampling distance for this line. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 0 [VKDOOM]
      lm_sampledist_top = <int>;     // lightmap customizable sampling distance for this line's top part. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 0 [VKDOOM]
      lm_sampledist_mid = <int>;     // lightmap customizable sampling distance for this line's middle part. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 0 [VKDOOM]
      lm_sampledist_bot = <int>;     // lightmap customizable sampling distance for this line's bottom part. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 0 [VKDOOM]
   }

   sidedef
   {
      scalex_top = <float>;            // X scale for upper texture, Default = 1.0.
      scaley_top = <float>;            // Y scale for upper texture, Default = 1.0.
      scalex_mid = <float>;            // X scale for mid texture, Default = 1.0.
      scaley_mid = <float>;            // Y scale for mid texture, Default = 1.0.
      scalex_bottom = <float>;         // X scale for lower texture, Default = 1.0.
      scaley_bottom = <float>;         // Y scale for lower texture, Default = 1.0.
      offsetx_top = <float>;           // X offset for upper texture, Default = 0.0.
      offsety_top = <float>;           // Y offset for upper texture, Default = 0.0.
      offsetx_mid = <float>;           // X offset for mid texture, Default = 0.0.
      offsety_mid = <float>;           // Y offset for mid texture, Default = 0.0.
      offsetx_bottom = <float>;        // X offset for lower texture, Default = 0.0.
      offsety_bottom = <float>;        // Y offset for lower texture, Default = 0.0.
                                       // When global texture offsets are used they will
                                       // be added on top of these values.
      light = <integer>;               // This side's light level. Default is 0.
      lightabsolute = <bool>;          // true = 'light' is an absolute value. Default is 
                                       // relative to the owning sector's light level.
      light_top = <integer>;           // This side's top tier light level. Default is 0.
      lightabsolute_top = <bool>;      // true = 'light_top' is an absolute value. Default is
                                       // relative to the sidedef's resulting light level.
      light_mid = <integer>;           // This side's mid tier light level. Default is 0.
      lightabsolute_mid = <bool>;      // true = 'light_mid' is an absolute value. Default is
                                       // relative to the sidedef's resulting light level.
      light_bottom = <integer>;        // This side's bottom tier light level. Default is 0.
      lightabsolute_bottom = <bool>;   // true = 'light_bottom' is an absolute value. Default is
                                       // relative to the sidedef's resulting light level.
      lightfog = <bool>;               // true = This side's relative lighting is used even in
                                       // foggy sectors. Default is to disable relative
                                       // lighting in foggy sectors.
      nofakecontrast = <bool>;         // Disables use of fake contrast on this sidedef.
      smoothlighting = <bool>;         // Use smooth fake contrast.
      clipmidtex = <bool>;             // Side's mid textures are clipped to floor and ceiling.
      wrapmidtex = <bool>;             // Side's mid textures are wrapped.
      nodecals = <bool>;               // Disables decals on the sidedef.
	  
	  nogradient_top = <bool>;	    // disables color gradient on upper tier. (Hardware rendering only.)
	  flipgradient_top = <bool>;    // flips gradient colors on upper tier. (Hardware rendering only.)
	  clampgradient_top = <bool>;   // clamps gradient on upper tier to actual bounds (default is the entire front sector height, hardware rendering only.)
	  useowncolors_top = <bool>;    // Set to 1 to use the colors set in the sidedef. Default is true if uppercolor or lowercolor are set, otherwise it's false
	  uppercolor_top = <int>;       // Material color of the top of the upper tier.
	  lowercolor_top = <int>;       // Material color of the bottom of the upper tier. (Hardware rendering only.)
	  
	  nogradient_mid = <bool>;	    // disables color gradient on middle tier. (Hardware rendering only.)
	  flipgradient_mid = <bool>;    // flips gradient colors on middle tier. (Hardware rendering only.)
	  clampgradient_mid = <bool>;   // clamps gradient on middle tier to actual bounds (default is the entire front sector height, hardware rendering only.)
	  useowncolors_mid = <bool>;    // Set to 1 to use the colors set in the sidedef. Default is true if uppercolor or lowercolor are set, otherwise it's false
	  uppercolor_mid = <int>;       // Material color of the top of the middle tier.
	  lowercolor_mid = <int>;       // Material color of the bottom of the middle tier. (Hardware rendering only.)

	  nogradient_bottom = <bool>;   // disables color gradient on lower tier. (Hardware rendering only.)
	  flipgradient_bottom = <bool>; // flips gradient colors on lower tier. (Hardware rendering only.)
	  clampgradient_bottom = <bool>;// clamps gradient on lower tier to actual bounds (default is the entire front sector height, hardware rendering only.)
	  useowncolors_bottom = <bool>; // Set to 1 to use the colors set in the sidedef. Default is true if uppercolor or lowercolor are set, otherwise it's false
	  uppercolor_bottom = <int>;    // Material color of the top of the lower tier.
	  lowercolor_bottom = <int>;    // Material color of the bottom of the lower tier. (Hardware rendering only.)

      useowncoloradd_top = <bool>;  // Controls where the advanced colorization properties are taken from.
      useowncoloradd_mid = <bool>;  // 0: From the containing sector, 1: from the given part of the linedef itself
      useowncoloradd_bottom = <bool>;  // Default for all 3 is 0.
      coloradd_top = <int>;         // Additive material color to apply to top section of sidedef. Default is black (0x000000)
      coloradd_mid = <int>;         // Additive material color to apply to middle section of sidedef. Default is black (0x000000)
      coloradd_bottom = <int>;      // Additive material color to apply to bottom section of sidedef. Default is black (0x000000)
      colorization_top = <int>;     // Sets a colorization record for the upper texture. Colorization records must be defined in TEXTURES.
      colorization_mid = <int>;     // Sets a colorization record for the middle texture. Colorization records must be defined in TEXTURES.
      colorization_bottom = <int>;  // Sets a colorization record for the lower texture. Colorization records must be defined in TEXTURES.

      lm_sampledist = <int>;        // lightmap customizable sampling distance for this sidedef. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 0 [VKDOOM]
      lm_sampledist_top = <int>;    // lightmap customizable sampling distance for this sidedef's top part. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 0 [VKDOOM]
      lm_sampledist_mid = <int>;    // lightmap customizable sampling distance for this sidedef's middle part. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 0 [VKDOOM]
      lm_sampledist_bot = <int>;    // lightmap customizable sampling distance for this sidedef's bottom part. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 0 [VKDOOM]
	  
	  skew_top = <int>;             // enables skewing of wall textures, the skewing angle will be aligned to one of the 4 planes touching the floor. 
      skew_middle = <int>;          // Vertical texture alignment defines the position at the leftmost point of the wall.
      skew_bottom = <int>;          // Possible values: 0 = no skewing, 1 = align to front floor, 2 = align to front ceiling, 3 = align to back floor, 4 = align to back ceiling.
	                                // Front/Back are relative to the sidedef, not the owning linedef. Default = 0.
									
      xscroll  = <float>;           // wall scrolling X speed in map units per tic.
      yscroll  = <float>;           // wall scrolling Y speed in map units per tic.
      xscrolltop  = <float>;        // upper wall scrolling X speed in map units per tic.
      yscrolltop  = <float>;        // upper wall scrolling Y speed in map units per tic.
      xscrollmid  = <float>;        // mid wall scrolling X speed in map units per tic.
      yscrollmid  = <float>;        // mid wall scrolling Y speed in map units per tic.
      xscrollbottom  = <float>;     // lower wall scrolling X speed in map units per tic.
      yscrollbottom  = <float>;     // lower wall scrolling Y speed in map units per tic.
									

   }

   sector
   {
      xpanningfloor = <float>;        // X texture offset of floor texture, Default = 0.0.
      ypanningfloor = <float>;        // Y texture offset of floor texture, Default = 0.0.
      xpanningceiling = <float>;      // X texture offset of ceiling texture, Default = 0.0.
      ypanningceiling = <float>;      // Y texture offset of ceiling texture, Default = 0.0.
      xscalefloor = <float>;          // X texture scale of floor texture, Default = 1.0.
      yscalefloor = <float>;          // Y texture scale of floor texture, Default = 1.0.
      xscaleceiling = <float>;        // X texture scale of ceiling texture, Default = 1.0.
      yscaleceiling = <float>;        // Y texture scale of ceiling texture, Default = 1.0.
      rotationfloor = <float>;        // Rotation of floor texture in degrees, Default = 0.0.
      rotationceiling = <float>;      // Rotation of ceiling texture in degrees, Default = 0.0.
      ceilingplane_a = <float>;       // Define the plane equation for the sector's ceiling. Default is a horizontal plane at 'heightceiling'.
      ceilingplane_b = <float>;       // 'heightceiling' will still be used to calculate texture alignment.
      ceilingplane_c = <float>;       // The plane equation will only be used if all 4 values are given.
      ceilingplane_d = <float>;       // The plane is defined as a*x + b*y + c*z + d = 0 with the normal vector pointing downward.
      floorplane_a = <float>;         // Define the plane equation for the sector's floor. Default is a horizontal plane at 'heightfloor'.
      floorplane_b = <float>;         // 'heightfloor' will still be used to calculate texture alignment.
      floorplane_c = <float>;         // The plane equation will only be used if all 4 values are given.
      floorplane_d = <float>;         // The plane is defined as a*x + b*y + c*z + d = 0 with the normal vector pointing upward.
      lightfloor = <integer>;         // The floor's light level. Default is 0.
      lightceiling = <integer>;       // The ceiling's light level. Default is 0.
      lightfloorabsolute = <bool>;    // true = 'lightfloor' is an absolute value. Default is
                                      // relative to the owning sector's light level.
      lightceilingabsolute = <bool>;  // true = 'lightceiling' is an absolute value. Default is
                                      // relative to the owning sector's light level.
      alphafloor = <float>;           // translucency of floor plane (only has meaning with Sector_SetPortal) Default is 1.0.
      alphaceiling = <float>;         // translucency of ceiling plane (only has meaning with Sector_SetPortal) Default is 1.0.
      renderstylefloor = <string>;    // floor plane renderstyle (only has meaning with Sector_SetPortal); not implemented yet in software renderer
                                      // can be "translucent" or "add", default is "translucent".
      renderstyleceiling = <string>;  // ceiling plane renderstyle (only has meaning with Sector_SetPortal); not implemented yet in software renderer
                                      // can be "translucent" or "add", default is "translucent".
      gravity = <float>;              // Sector's gravity. Default is 1.0.
      lightcolor = <integer>;         // Sector's light color as RRGGBB value, default = 0xffffff.
      fadecolor = <integer>;          // Sector's fog color as RRGGBB value, default = 0x000000.
      desaturation = <float>;         // Color desaturation factor. 0 = none, 1 = full, default = 0.
      silent = <bool>;                // Actors in this sector make no sound,
      nofallingdamage = <bool>;       // Falling damage is disabled in this sector
      noattack = <bool>;              // Blocks monster attacks in this sector.
      dropactors = <bool>;            // Actors drop with instantly moving floors (*)
      norespawn = <bool>;             // Players can not respawn in this sector
      soundsequence = <string>;       // The sound sequence to play when this sector moves. Placing a
                                      // sound sequence thing in the sector will override this property.
      hidden = <bool>;                // if true this sector will not be drawn on the textured automap.
      waterzone = <bool>;             // Sector is under water and swimmable
      moreids = <string>;             // Additional sector IDs/tags, specified as a space separated list of numbers (e.g. "2 666 1003 4505")
      damageamount = <int>;           // Amount of damage inflicted by this sector, default = 0. If this is 0, all other damage properties will be ignored.
                                      // Setting damage through these properties will override any damage set through 'special'.
                                      // Setting damageamount to a negative value will create a healing sector.
      damagetype = <string>;          // Damage type for sector damage, Default = "None". (generic damage)
      damageinterval = <int>;         // Interval in tics between damage application, default = 32.
      leakiness = <int>;              // Probability of leaking through radiation suit (0 = never, 256 = always), default = 0.
      damageterraineffect = <bool>;   // Will spawn a terrain splash when damage is inflicted. Default = false.
      damagehazard = <bool>;          // Changes damage model to Strife's delayed damage for the given sector. Default = false.
      hurtmonsters = <bool>;          // Non-players like monsters and decorations are hurt by this sector in the same manner as player. Doesn't work with damagehazard.
      harminair = <bool>;             // Actors in this sector are harmed by the damage effects of the floor even if they aren't touching it.
      floorterrain = <string>;        // Sets the terrain for the sector's floor. Default = 'use the flat texture's terrain definition.'
      ceilingterrain = <string>;      // Sets the terrain for the sector's ceiling. Default = 'use the flat texture's terrain definition.'
      floor_reflect = <float>;        // reflectiveness of floor (OpenGL only, not functional on sloped sectors)
      ceiling_reflect = <float>;      // reflectiveness of ceiling (OpenGL only, not functional on sloped sectors)
      fogdensity = <integer>;         // Sets an explicit fog density for the sector, overriding the default calculation from the light level. Value range is 0-510,
                                      // 0 meaning that the default is to be used, 2 equalling the density of a light level of 250, and 255 equalling the density of
                                      // a light level of 0.  (OpenGL only)
      floorglowcolor = <integer>;     // Sector's floor glow color as RRGGBB value, default = 'use texture's definition'. Set to -1 to disable glowing. (OpenGL 3.x and newer only)
      floorglowheight = <float>;      // Height of floor glow. This only has an effect for the sector's own glow color, but not for a texture based glow. (OpenGL 3.x and newer only)
      ceilingglowcolor = <integer>;   // Sector's ceiling glow color as RRGGBB value, default = 'use texture's definition'. Set to -1 to disable glowing. (OpenGL 3.x and newer only)
      ceilingglowheight = <float>;    // Height of ceiling glow. This only has an effect for the sector's own glow color, but not for a texture based glow. (OpenGL 3.x and newer only)
      color_floor = <int>;            // Material color of sector's floor. Default is white (0xffffff)
      color_ceiling = <int>;          // Material color of sector's ceiling. Default is white (0xffffff)
      color_walltop = <int>;          // Material color of top of sector's sidedefs. In OpenGL 2.x and the software renderer this will define the entire wall's color) Default is white (0xffffff)
      color_wallbottom = <int>;       // Material color of bottom of sector's sidedefs (OpenGL 3.x and later only) Default is white (0xffffff)
      color_sprites = <int>;          // Material color of sprites in sector. Default is white (0xffffff)

      coloradd_floor = <int>;         // Additive material color applied to the sector floor. Default is black (0x000000)
      coloradd_ceiling = <int>;       // Additive material color applied to the sector ceiling. Default is black (0x000000)
      coloradd_sprites = <int>;       // Additive material color applied to sprites within the sector. Default is black (0x000000)
      coloradd_walls = <int>;         // Additive material color applied to walls within the sector. Default is black (0x000000)

      colorization_floor = <int>;     // Sets a colorization record for the floor texture. Colorization records must be defined in TEXTURES.
      colorization_ceiling = <int>;     // Sets a colorization record for the ceiling texture. Colorization records must be defined in TEXTURES.

      noskywalls = <bool>;            // If true, do not draw skybox walls above/below this sector

      portal_ceil_blocksound = <bool>;     // ceiling portal blocks sound.
      portal_ceil_disabled = <bool>;       // ceiling portal disabled.
      portal_ceil_nopass = <bool>;         // ceiling portal blocks movement if true.
      portal_ceil_norender = <bool>;       // ceiling portal not rendered.
      portal_ceil_overlaytype = <string>;  // defines translucency style, can either be "translucent" or "additive". Default is "translucent".
      portal_floor_blocksound = <bool>;    // floor portal blocks sound.
      portal_floor_disabled = <bool>;      // floor portal disabled.
      portal_floor_nopass = <bool>;        // ceiling portal blocks movement if true.
      portal_floor_norender = <bool>;      // ceiling portal not rendered.
      portal_floor_overlaytype = <string>; // defines translucency style, can either be "translucent" or "additive". Default is "translucent".

      healthfloor = <int>;            // Amount of hitpoints for this sector (includes floor and bottom-outside linedef sides)
      healthfloorgroup = <int>;       // ID of destructible object to synchronize hitpoints (optional, default is 0)
      healthceiling = <int>;          // Amount of hitpoints for this sector (includes ceiling and top-outside linedef sides)
      healthceilinggroup = <int>;     // ID of destructible object to synchronize hitpoints (optional, default is 0)
      health3d = <int>;               // Amount of hitpoints for this sector (includes 3D floors)
      health3dgroup = <int>;          // ID of destructible object to synchronize hitpoints (optional, default is 0)
	  
      xscrollfloor = <float>;         // X map units per frame to scroll the floor.
      yscrollfloor = <float>;         // Y map units per frame to scroll the floor.
      scrollfloormode = <int>;        // Floor scroll mode bit mask (1 = scroll textures, 2 = carry static objects, 4 = carry players, 8 = carry monsters.
      xscrollceiling = <float>;       // X map units per frame to scroll the ceiling.
      yscrollceiling = <float>;       // Y map units per frame to scroll the ceiling.
      scrollceilingmode = <int>;      // ceiling scroll mode bit mask (1 = scroll textures, 2 = carry static objects, 4 = carry players, 8 = carry monsters.
	  
	  scroll_ceil_x = <float>;        // deprecated Eternity based alternatives for the above. 
	  scroll_ceil_y = <float>;        // Due to using unintuitive units of measurement and a more limited feature set they should not be used anymore.	
	  scroll_ceil_type = <string>;
	  scroll_floor_x = <float>;
	  scroll_floor_y = <float>;
	  scroll_floor_type = <string>;
	  
	  friction = <float>;             // sets the sector's friction factor. Must be between 0 and 1.
	  movefactor = <float>            // sets the sector's movement acceleration factor. Must be > 0.
	  
	  skyfloor = <string>             // defines lower sky for this sector.
	  skyceiling = <string>           // defines upper sky for this sector.
	  skyfloor2 = <string>             // defines secondary lower sky for this sector. (for lightning or transparent layers)
	  skyceiling2 = <string>           // defines secondary upper sky for this sector.
	  
	  colormap = <string>;            // only provided for backwards compatibility. Do not use in GZDoom projects.
	  
      xthrust = <float>;              // applies thrust to actors - x-magnitude
      ythrust = <float>;              // applies thrust to actors - y-magnitude
      thrustgroup = <int>;            // specifies which actors get thrusted. Bitfield with (1 = static objects, 2 = player, 4 = monsters, 8 = projectiles, 16 = actors with +WINDTHRUST)
      thrustlocation = <int>;         // specifies where in the sector actors get thrusted: (1 = on the ground, 2 = in the air, 4 = on the ceiling)
	  

      * Note about dropactors

      The spec requires this to be false by default. Currently, however, ZDoom assumes this to be true
      for Doom format maps so any map converter converting to the ZDoomTranslated namespace should
      set this flag for each tagged sector.

      lm_sampledist_floor = <int>;      // lightmap customizable sampling distance for this sector's floor. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 0 [VKDOOM]
      lm_sampledist_ceiling = <int>;    // lightmap customizable sampling distance for this sector's ceiling. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 0 [VKDOOM]
      lm_dynamic = <bool>;              // lightmap marks a sector's lightmaps as dynamic so that they may be updated in realtime (used for flickering lights, changing a lightmap light's position, color etc). Default = false [VKDOOM]
   }

   thing
   {
      skill# = <bool>           // Unlike the base spec, # can range from 1-16.
      class# = <bool>           // Unlike the base spec, # can range from 1-16.
      conversation = <int>      // Assigns a conversation dialogue to this thing.
                                // Parameter is the conversation ID, 0 meaning none.
      countsecret = <bool>;     // Picking up this actor counts as a secret.
      nocount = <bool>;         // When true, object does not count toward kills or items.
      arg0str = <string>;       // Alternate string-based version of arg0
      arg1str = <string>;       // Alternate string-based version of arg1
      gravity = <float>;        // Set per-actor gravity. Positive values are multiplied with the class's property, 
                                // negative values are used as their absolute. Default = 1.0.

      health = <float>;         // Set per-actor health. Positive values are multiplied with the class's property,
                                // negative values are used as their absolute. Default = 1.

      renderstyle = <string>;   // Set per-actor render style, overriding the class default. Possible values can be "normal",
                                // "none", "add" or "additive", "subtract" or "subtractive", "stencil", "translucentstencil", 
                                // "addstencil", "shaded", "addshaded", "translucent", "fuzzy", "optfuzzy", "soultrans" and "shadow". 
                                // Default is an empty string for no change.
      fillcolor = <integer>;    // Fill color used by the "stencil", "addstencil" and "translucentstencil" rendestyles, as RRGGBB value, default = 0x000000.
      alpha = <float>;          // Translucency of this actor (if applicable to renderstyle), default is 1.0.
      score = <int>;            // Score value of this actor, overriding the class default if not null. Default = 0.
      pitch = <integer>;        // Pitch of thing in degrees. Default = 0 (horizontal).
      roll = <integer>;         // Pitch of thing in degrees. Default = 0 (horizontal).
      scalex = <float>;         // Horizontal scaling on thing. Default = 0 (ignored).
      scaley = <float>;         // Vertical scaling on thing. Default = 0 (ignored).
      scale = <float>;          // Vertical and horizontal scaling on thing. Default = 0 (ignored).
      floatbobphase = <int>;    // Sets the thing's floatbobphase. Valid phase values are 0-63. Default = -1 (use actor class default).

      // ZDRayInfo fields [VKDOOM]
      lm_sampledist = <int>;        // lightmap sample distance for the entire map. Defines the map units each lightmap texel covers. Must be in powers of two. Default = 8 [VKDOOM]
      lm_suncolor = <int>;          // lightmap sun color. Default is white (0xFFFFFF). [VKDOOM]
      lm_sunintensity = <float>;    // lightmap sun intensity multiplier. Default = 1.0 [VKDOOM]
      lm_ao = <bool>;               // enables ambient occlusion baking with VKTool. [VKDOOM]
      lm_bounce = <bool>;           // enables bounce light baking with VKTool. [VKDOOM]

      // Dynamic and lightmap light fields [VKDOOM]
      light_softshadowradius = <float>;    // lightmap light and raytraced dynamic light soft shadow amount. Higher values produce softer shadows. Default = 5.0 [VKDOOM]
      light_strength = <float>;            // Light strength for Inverse-square falloff lights. Default = 0.0 (auto) [VKDOOM]
      light_noshadowmap = <bool>;          // Disable shadows for light [VKDOOM]
      light_dontlightactors = <bool>;      // Don't light actors [VKDOOM]
      light_dontlightmap = <bool>;         // Don't light map geometry [VKDOOM]

      friendlyseeblocks = <int>;    // How far (in block units) a friendly monster can see other monsters. Default 10

      * Note about arg0str

      For things with ACS specials (80-86 and 226), if arg0str is present and non-null, it
      will be used as the name of the script to execute, and arg0 will be ignored.
      On dynamic lights, arg0str can be used to set a color by name, this will supersede all args which are normally used to define a color.
   }



*** Special notes for map format conversions:

   Setting the line's ID via special is not supported so any special using
   this option must be converted to use the line's ID field instead.
   Unless mentioned differently the arg being used to define the line ID
   should be set to 0.
   The following line specials are affected:

   121: Line_SetIdentification, arg 0
   208: TranslucentLine, arg0 (arg0 must be preserved)
     1: Polyobj_StartLine, arg3
     5: Polyobj_ExplicitLine, arg4
   181: Plane_Align, arg2
   215: Teleport_Line, arg0
   222: Scroll_Texture_Model, arg0 (arg0 must be preserved)
   160: Sector_3DFloor, arg4 (both uses as high-byte of tag and line ID are not supported in UDMF and must be remapped)

   Some specials also allow setting the extended flags. These must also be
   converted to explicitly setting the flags through the defined map fields.
   This affects the following specials:

   121: Line_SetIdentification, arg1
   208: TranslucentLine, arg3

   These args are to be converted as follows to flags, bit by bit:

   Bit 0 (Value   1): zoneboundary
   Bit 1 (Value   2): jumpover
   Bit 2 (Value   4): blockfloaters
   Bit 3 (Value   8): clipmidtex
   Bit 4 (Value  16): wrapmidtex
   Bit 5 (Value  32): midtex3d
   Bit 6 (Value  64): checkswitchrange
   Bit 7 (Value 128): firstsideonly
   When used in special 208 this arg should be cleared afterward.

   Special 121 is not being used by UDMF maps in ZDoom and should be completely
   deleted after conversion.


=======================================
Changelog
=======================================

1.1: 27.05.2008
Changed default light mode for sectors and sidedefs to relative and renamed
associated properties to avoid having a non-intuitive standard value for the
light field.
Added 'nofakecontrast' option to sidedefs.

1.2 21.08.2008
Added smooth lighting option to linedefs

1.3 12.12.2008
Added NoRespawn sector flag
Fixed lightfloor and lightceiling properties for sectors. They are of type 
integer, not float

1.4 27.01.2009
Changed description of class and skill thing flags to avoid the impression that
this uses array syntax. No functional changes

1.5 22.02.2009
Added blockprojectiles to lines and firstsideonly to conversion notes

1.6 28.04.2009
Added blockuse line flag.

1.7 07.06.2009
Added sidedef scaling properties and side specific clipmidtex and wrapmidtex.

1.8 16.07.2009
Added NoDecals sidedef option
Fixed conversion specifications for TranslucentLine special.

1.9 17.04.2010
Changed node specifications to deprecate compression of node lump.

1.10 25.04.2010
Added 'playeruseback' line trigger flag.

1.11 07.08.2010
Added 'soundsequence' sector property.

1.12 22.08.2010
Added 'conversation' thing property.

1.13 29.08.2010
Added 'hidden' sector property.

1.14 19.09.2010
Added 'countsecret' actor property.

1.15 14.12.2010
Added vertex floor and ceiling height properties

1.16 23.01.2011
Added alphaceiling and alphafloor sector properties
Added blocksight linedef flag
Removed remarks of 8 being the maximum number of player classes/skill levels the menu can handle so the spec now properly lists 16 as limit.

1.17 12.02.2011
Added renderstyleceiling and renderstylefloor sector properties
Added Sector_Set3DFloor to list of specials that need to be handled for line ID remapping

1.18 17.02.2012
Added arg0str linedef property.
Standardized whitespace.

1.19 24.02.2012
Added back locknumber property.

1.20 25.02.2012
Added arg0str thing property.

1.21 09.08.2013
Added waterzone sector property.

1.22 12.04.2014
Added transparent line property (to be folded back to core UDMF standard), and health, score, renderstyle, fillcolor, alpha, scale, scalex, scaley, pitch and roll thing properties.

1.24 14.05.2014
Added plane equations for sector slopes. (Please read carefully to ensure proper use!)
Changed language describing the DIALOGUE lump to mention USDF as an option.

1.25 19.04.2015
Added 'moreids' for linedefs and sectors.

1.26 05.01.2016
added clarification about character encoding
added sector damage properties.

1.27 05.01.2017
floor_reflect and ceiling_reflect.

1.28 28.01.2017
sector material colors.

1.29 04.02.2018
arg0str in dynamic lights.

1.30 20.05.2018
Added automapstyle and revealed linedef properties.
Replaced tabs with spaces.

1.31 31.10.2018
Added destructible level geometry properties.

1.32 22.12.2019
Coloriation options added

1.33 28.06.2021
Blocklandmonsters MBF21 flag

1.34 06.11.2021
Added separate light levels for sidedef tiers (top/mid/bottom)

1.35 11.09.2023
Added/updated ZDRay/lightmap-related properties.

1.36 15.09.2023
fixed omissions: Blocklandmonsters and Blockfloaters line flags.

1.37 20.10.2023
Sidedef skewing properties added

1.38 30.09.2024
Hurtmonsters and harminair added.

===============================================================================
EOF
===============================================================================
