Bodies

People are built on the Genesis 8 Female and Male figures. Each figure is described by a .ulbody file in Bodies/:

iniDisplayName: Genesis 8 Female
Gender: Female
MeshId: /Game/Genesis8/Female.Female
AnimationId: Idle_F_Daz.fbx
Genital: Vagina
PenisMeshId: /Game/Heavy/Daz/Bridget/futa/TAB_Gen3F_27097.TAB_Gen3F_27097
Material.Torso: /Game/Heavy/Daz/Bridget/B_Torso.B_Torso
Material.Face: /Game/Heavy/Daz/Bridget/B_Face.B_Face

A body can replace the skin pictures with files, keeping everything the skin material does on top of them: Textures/<name>/<slot>_BC.png (and _N, _M), beside the mesh file when MeshId is a mod file, else beside the .ulbody (Bodies/Textures/G8_Female/Torso_BC.png for Bodies/G8_Female.ulbody). Default_BC.png answers for every slot without its own.

The base game ships three: G8_Female, G8_Male, and G8_Male_FemGen (the male figure with a vagina).

#Skins: .ulskin

A skin is the set of pictures a person's body wears: colour, normal, specular, roughness and subsurface, one set per Genesis 8 UV tile. Each person draws one, so two people of the same tone can still look like different people. Skins live in Skins/, one folder each:

ini# Skins/Female/Hannah/Hannah.ulskin
DisplayName: Hannah
Gender: Female
Tone: 0.15
Races: Caucasian

beside its pictures, <Tile>_<map>.png for each tile the body names in its SkinTile. lines:

A .dds (DXT1/DXT5, with mips) of the same name next to a .png is loaded instead, which is faster. Fill the whole picture, not only the UV islands: past the islands a black background shows up as pale dotted lines along the tile seams once the game samples the smaller mips. The face is drawn by a shader without subsurface scattering that renders the same colour redder than the body (green about ×0.88, blue ×0.82): paint Face_BC correspondingly paler, or the face reads as a red mask on a paler neck. The tiles are the Genesis 8 Female/Male UV layout at 2048×2048; GenitalF is the female graft's layout (GP_* slots, Golden Palace's default UV set: its own pictures use the Golden Palace set and must be re-projected), GenitalM the male genital base (Torso_ncl_1), Shaft the male figure's penis (slot Default), which uses XY's XY3 UV set: the whole penis sits in a small band of the square around u 0.50, v 0.89 (top-down), so paint it at 4096 and keep it matte (a glossy roughness draws a white streak along its sides).

A person picks the skin of their gender whose Tone is nearest to theirs, preferring their race. Makeup, tattoos, tan lines, body hair and injuries are layered on top of any skin, so they need nothing from it. The base game ships its own skins in ul_Base/Skins/; a mod adds more by shipping its own folders, and a skin with the same file name replaces the earlier one.

#Height: .ulheight

A person's height (the creator's Height slider, the SCALE Height line of a preset) shortens or lengthens the skeleton itself, the way Daz's height morphs do, so a short person is a short person and not a shrunk one: the head stays adult-sized, the legs and torso shorten, and clothes, hair and every animation follow. The bone changes come from a .ulheight file in Bodies/:

json{
 "morph": "3FootTall",
 "meshes": ["/Game/Genesis8/Female.Female"],
 "heightCm": { "base": 179.3, "atMin": 179.3, "atMax": 91.9 },
 "bones": {
  "lThighBend": [-0.2, -0.6, -0.137],
  "head": [0.1, 0.1, 0.1]
 }
}

Height value 0 is the figure as modelled, 1 is the morph at 100% (3FootTall: about half height), negative values make the person taller. The feet stay on the floor; in a sex animation the hips stay where the clip puts them instead.

The base game's files (G8_Female.ulheight, G8_Male.ulheight) are made from Daz's 3FootTall morph. To make one from another morph, in the game repository:

1. In Daz Studio, select the figure with no other shape dialled, set the morph name in Tools/Daz/MeasureHeightMorph.dsa, and run it from the Script IDE. It writes <Figure>_<Morph>.json next to the script.
2. python Tools/Daz/make_lpheight.py <that json> Bodies/My.ulheight /Game/Genesis8/Female.Female

Do not also export the height morph into the body FBX and dial it: Daz bakes the skinned result of the bone scaling into the exported blendshape, so the morph and the bones together would shrink the body twice. A later mod's file for the same mesh replaces an earlier one.

#Penis controls: .ulpenis

The penis graft's pose controls ("Penis bend", "Penis up-down", "Penis side-side"...) are, in Daz, formulas that turn and move the Penis* bones, with no vertex changes: an FBX export cannot carry them. The game applies the same formulas from a .ulpenis file in Bodies/, which also says how an erection is made:

json{
 "bones": { "Penis-root": { "x": [1, 0, 0], "y": [0, 0.17, 0.98], "z": [0, -0.98, 0.17] } },
 "controls": {
  "Penis up-down": { "min": -1, "max": 1, "drives": [ { "bone": "Penis-root", "channel": "rotation/x", "factor": -25 } ] }
 },
 "erection": { "aim_control": "Penis up-down", "aim_degrees_per_unit": -107, "hold": {} }
}

ul_Base/Bodies/XY.ulpenis is generated from the XY graft by python Tools/DazMakeup/export_penis_controls.py in the game repository. A later mod's control replaces an earlier one of the same name.

#Bodies that are not Genesis 8

A mod can add a whole different figure: a VRoid or VRM avatar, a Mixamo character, a modder's orc, a robot. It needs nothing but a rigged mesh and a short .ulbody:

ini# Bodies/VRoidSample.ulbody
DisplayName: VRoid sample
Gender: Female
Race: VRoidSample
MeshId: Bodies/VRoidSample.glb

with the mesh at Meshes/Bodies/VRoidSample.glb (.glb, .gltf or .fbx; a .vrm is a .glb, rename it). The official Example body mod (ul_ExampleBody) is exactly this, ready to copy.

It plays every animation in the game. Every clip, pose, scene and walk is made for the Genesis 8 skeleton, so a person wearing such a body keeps an unseen Genesis 8 body that plays all of it, and the foreign one copies its pose every frame: each limb points where the Genesis 8 limb points, so a rig modelled in a T-pose and one in an A-pose end up holding the same arms, and the hips travel in proportion to the leg length.

Which bone is which is found by name, from the Rigs/*.ulrig tables of every enabled mod. ul_Base/Rigs/humanoid.ulrig already knows Mixamo (mixamorig:LeftUpLeg), the Unreal mannequin (thigh_l), VRoid/VRM (J_Bip_L_UpperLeg), Character Creator, Rigify and 3ds Max Biped. Names are compared without case, namespace (mixamorig:) or separators. A rig it does not know names its bones in the .ulbody, one line per Genesis 8 bone:

iniBone.hip: Root_Pelvis
Bone.lShldrBend: Arm_L_01
Bone.lThighBend: Leg_L_Upper

The Genesis 8 bones it follows: hip, abdomenLower, abdomenUpper, chestUpper, neckLower, head; per side (l/r) Collar, ShldrBend, ForearmBend, Hand, Thumb1-3, Index1-3, Mid1-3, Ring1-3, Pinky1-3, ThighBend, Shin, Foot, Toe. Hips, head, both thighs and both upper arms are required; anything else missing just keeps its rest pose. The log says what was matched: ForeignBody: VRoidSample - 49 of 52 G8 bones matched ... Unmatched: .... Extra bones (a tail, a cape, a weapon) keep their rest pose, and a sleeve or skirt bone that sits where a limb starts moves with that limb.

To share a table for a whole rig family, ship your own Rigs/<name>.ulrig:

ini# <G8 bone>: <name>, <name>, ...
lShldrBend: arm_l_01, upperarm_left

Textures come with the .glb. Loose pictures replace them per material slot: Meshes/Bodies/Textures/<mesh name>/<slot>_BC.png (colour), _N.png (normal), _MR.png (glTF metallic-roughness); Default_BC.png answers for every slot without its own.

Thumbnail: Bodies/Thumbs/<file name>.png beside the .ulbody (512×512 works well) is the tile on the creator's Body page.

What does not carry over to a foreign body: Genesis 8 clothing and hair (they are hidden while it is worn), the creator's morph sliders, makeup, tattoos and skin tone. It is not offered for a person under 18. A non-humanoid (four legs, wings for arms) cannot play human animations.

#What this means for modders

Everything wearable and every animation is authored against the Genesis 8 figures: Genesis 8, with its bone names. Clothing and hair made for another figure will not fit. A body for another figure can be added as above; it plays the game's animations but wears its own clothes.