Glossary

3D terms, briefly explained

Short, practical explanations of 3D terms for game developers: PBR, UV mapping, normal maps, LOD, polycount, rigging, Draco, glTF, FBX and CC0.

CC0 The public domain dedication, and the freest "license" there is. Draco Compression An open mesh compression for glTF/GLB files that makes geometry much smaller to download. FBX A proprietary but widely supported interchange format for meshes, rigs and animation. glTF / GLB The open standard 3D format, often called "the JPEG of 3D". LOD (Level of Detail) Several versions of a model with decreasing detail that the engine swaps by camera distance. Low Poly A 3D art style using deliberately few polygons with flat-shaded surfaces. Normal Map A texture that stores surface directions to fake fine detail without extra geometry. OBJ A simple, decades-old text format for static meshes that almost every 3D program can open. PBR Physically based rendering: materials that react to light in a consistent, realistic way. Pivot Point The point an object is positioned, rotated and scaled around: its local origin. Polycount The number of polygons (usually triangles) in a 3D model. Retargeting Transferring animations from one skeleton to another with different proportions or bone names. Rigging Adding a skeleton of bones to a mesh and binding its vertices to it so it can be animated. Texel Density How many texture pixels cover one meter of surface, the key to evenly sharp textures. Topology How a mesh's polygons are structured and connected. USDZ Apple's packaged USD format for AR, which opens in AR Quick Look on iPhone and iPad. UV Mapping Unfolding a 3D surface into 2D texture coordinates so an image can be wrapped onto it. Vertex Colors Color stored directly on mesh vertices, with no texture files needed.