Optimisation
Read these pages in order, or jump to the one you need.
- Polygon and triangle budgetsTopicHow many triangles an asset or a frame can afford, with dozens of published examples from real games, platforms and asset types, and a method for setting a budget yourself.
- Level of detail (LOD)TopicSwapping an asset for cheaper versions as it gets smaller on screen, from classic LOD chains and HLOD to impostors and Nanite.
- Impostors and billboardsKey termFlat cards that show pre-rendered views of a 3D object, used as the cheapest distant LOD for trees, rocks and buildings. Billboards use a few fixed views; octahedral impostors pack many views into one atlas.
- Hierarchical LOD (HLOD)Key termLevel of detail for groups of objects. Distant clusters of meshes are replaced by one merged, simplified or instanced proxy, cutting draw calls and keeping unloaded areas visible.
- InstancingKey termDrawing many copies of the same mesh and material in one batch, with only position, rotation, scale and a little custom data stored per copy. This is why kits, rocks and forests are cheap to draw.
- RetopologyTopicBuilding a new, cleaner and lighter mesh over a dense one, by hand or with auto-retopology tools, and when environment artists actually need it.
- DecimationKey termAutomatically reducing a mesh's triangle count while keeping its shape, usually producing messy triangles rather than clean quads.