Mesh simplification
Set vertex retention and error tolerance, with geometry and material overrides for mesh simplification.
Simplify is not Meshopt compression
Simplify reduces mesh complexity and can change a model’s shape. Meshopt compresses mesh data; the two options have different purposes. Start with a copy of your original model and enable only the optimization you want to evaluate. Use the result’s triangle and vertex counts as well as file size to judge the change.
Retention and error tolerance work together
Enable Simplify and expand its settings. Vertex retention is adjustable in 1% steps; lower values request a stronger reduction. Error tolerance starts at 0.01% and limits the permitted geometric error relative to the mesh scale. A strict error limit can stop reduction before the requested ratio is reached. It is not a percentage of visible image difference, and the requested ratio does not guarantee an exact final vertex count.
Override or protect selected parts
Automatic uses the global settings. Override sets retention and error tolerance for a material or geometry. Geometry overrides take precedence over material overrides, then global settings. Use Exclude for parts whose shape must be retained. Inspect the silhouette, seams and animated deformation after conversion; a static preview alone cannot validate every animation.