3D clothing design glossary

The technical words you meet when you start making clothing for Second Life and other virtual worlds, each explained in a sentence or two.

Software · Modelling · UVs and textures · Rigging · Files, export and selling

Software

Blender: Free, open-source 3D software. It is the standard program for modelling, UV mapping, rigging and exporting clothing for Second Life and most other virtual worlds.
Blender addon (add-on): A plug-in that adds tools to Blender. GALA and the Fur addon by SL Designers are Blender addons for clothing creators.
Marvelous Designer: Cloth simulation software in which a garment is sewn from flat patterns, like real tailoring, and draped on an avatar. Its project files end in .zprj.
Substance Painter: Texturing software by Adobe for painting materials directly onto a 3D model and exporting PBR texture maps (base colour, normal, roughness, metallic).
ZBrush: Digital sculpting software, used for high-detail work such as folds, wrinkles and seams before that detail is baked into a normal map.
Photoshop: Image editor used for painting and adjusting textures. Layered texture files are often shared as .psd.
Avastar: A third-party Blender addon with the Second Life avatar skeleton and tools for rigging and export.

Modelling

Mesh: A 3D object made of vertices, edges and faces. In Second Life, "mesh clothing" means clothing made as a 3D model outside the world and uploaded into it.
Vertex, edge, face (polygon): The building blocks of a mesh: points, the lines between them, and the surfaces they enclose. Faces with three corners are triangles (tris); with four, quads.
Topology: The way a mesh's faces are laid out. Good topology follows the shape and the places where it bends, so the garment deforms cleanly when the avatar moves.
Retopology: Rebuilding a dense or messy mesh as a clean, lighter one with the same shape.
High poly and low poly (HP / LP): A high-poly mesh carries all the fine detail; a low-poly mesh is the light version that is actually worn. The detail of the first is baked into textures for the second.
Sculpting: Shaping a mesh like clay with brushes, used for folds, wrinkles and soft forms.
Cloth simulation: Letting the computer drape fabric under gravity over a body, to get natural folds.
Subdivision: Splitting every face into smaller ones to make a surface smoother.
Triangle count (polycount): How many triangles a mesh has. Every virtual world limits or penalises heavy meshes, so clothing has to stay within a budget.
Mesh body: A replacement avatar body in Second Life, such as Maitreya, Legacy, Reborn or Kupra. Clothing is fitted and rigged separately for each body.

UVs and textures

UV map: The flat layout of a 3D surface, which tells the program where each part of a texture goes on the mesh. U and V are the two directions of that flat image.
UV unwrapping: Making the UV map: cutting the mesh along seams and laying it out flat, like opening a garment into its pattern pieces.
Seam: An edge where the mesh is cut for unwrapping. Seams are placed where they will be least visible.
Texel density: How much texture resolution each part of the surface gets. Even texel density keeps a garment equally sharp everywhere.
Texture (texture map): An image applied to a mesh through its UV map: colour, or data such as surface direction or roughness.
Baking: Calculating information once and saving it as a texture: the detail of a high-poly mesh as a normal map, or soft shadows as an ambient occlusion map.
Normal map: A texture that makes a flat surface catch light as if it had folds, stitches and seams, without adding polygons.
Ambient occlusion (AO) map: A texture of soft contact shadows - in folds, under collars - that gives depth.
PBR (physically based rendering): The modern material system: base colour, normal, roughness and metallic maps that react to light the way real surfaces do. Second Life supports PBR materials through glTF.
Base colour, roughness, metallic: The main PBR maps: the surface's colour, how matt or glossy it is, and whether it is metal.
Blinn-Phong (diffuse, normal, specular): Second Life's older material system, with diffuse, normal and specular maps. Many products offer both it and PBR.
Alpha: Transparency. In Second Life, alpha cuts also hide parts of the body under clothing.
Material (face): A part of a mesh that can carry its own texture and colour. Second Life allows up to eight per mesh object; texture changer HUDs work on them.

Rigging

Rigging: Connecting a mesh to a skeleton so that it moves with the avatar. Unrigged clothing is a stiff object; rigged clothing bends at the elbows and knees.
Armature (skeleton, bones): The set of bones that moves an avatar. Clothing is rigged to the same armature as the body it is worn on.
Skinning: Another word for binding a mesh to a skeleton: deciding which bones move which vertices.
Weight painting: Painting how strongly each bone pulls on each part of the mesh. It decides whether a sleeve bends smoothly or collapses.
Weight transfer: Copying weights from the body onto a garment as a starting point, to be corrected by hand afterwards.
Fitted mesh: Second Life rigging that also uses the avatar's collision-volume bones, so clothing follows body sliders such as breast, belly and hip size.
Bento: The extended Second Life skeleton, with extra bones for hands, face, wings and tails.
Shape keys (blendshapes, morphs): Stored alternative shapes of the same mesh that can be blended in. Used for body sliders in VRChat, The Sims 4 and others.
Refit: Adapting an existing garment to another body or shape instead of making it again.
Clipping (poke-through): The body showing through clothing in some pose. Fixed by fit, by weights, or by hiding the body underneath.

Files, export and selling

Collada (.dae): The file format Second Life accepts for mesh uploads, including rigged mesh.
FBX (.fbx): A common 3D exchange format with mesh, rig and animation, used for Unity (VRChat) and Roblox.
OBJ (.obj): A simple 3D format with mesh and UVs but no rig. Used to pass models between programs.
glTF (.gltf, .glb): A modern 3D format. Second Life uses it for PBR materials.
.blend: Blender's own project file.
LOD (level of detail): Lighter versions of a mesh shown from farther away. Second Life asks for them at upload.
Land impact: Second Life's measure of how much a rezzed object costs a region. Lighter meshes and good LODs keep it low.
Full perm: A Second Life item sold with copy, modify and transfer permissions, usually a mesh kit that other creators texture and resell under a licence.
HUD: An attachment shown on the wearer's screen in Second Life. A texture changer HUD lets customers change a product's colours and materials.
Dynamic clothing: Clothing that moves, sways or reacts instead of staying rigid on the body.

Learn them by doing

These words stop being vocabulary once you have made a garment. See the clothing design courses and the Blender addons.

Questions people ask

What is rigging in Second Life clothing?

Rigging connects a mesh garment to the avatar skeleton so that it bends and moves with the wearer. With fitted-mesh rigging it also follows the wearer's body shape sliders.

What is a UV map?

A UV map is the flat layout of a 3D surface. It tells the program which part of a texture image lands on which part of the mesh.

What is the difference between Blender, Marvelous Designer and Substance Painter?

They do different jobs. Blender is general 3D software: modelling, UVs, rigging and export. Marvelous Designer simulates cloth sewn from patterns. Substance Painter paints materials and textures onto a finished model.