Decimate Modifier
Reduces polygon count automatically
Also known as: Blender decimate · Blender reduce polycount · Blender collapse decimate · Blender decimate planar · Blender LOD decimate
Definition
The Decimate modifier lowers the polygon count of a mesh automatically. Collapse, the main mode, merges vertices to reach a Ratio, such as 0.5 for half the faces. Un-Subdivide reverses a subdivision, and Planar merges flat areas based on an angle. It is quick and works on any mesh, but it ignores edge flow, so the result is triangulated, uneven and unsuitable for animation or clean game assets.
In production
Use it for distant LODs, background props, scans and heavy sculpts where topology does not matter, and keep the UVs and silhouette by checking the result. For hero assets, retopologize by hand or with a quad remesher instead. Use vertex groups to protect important areas, and apply the modifier before export. Always check normals and shading after decimation, since it changes the surface.