Decimators

A jewelry STL can easily carry ten times the triangles the printer needs. The two Decimator commands lighten a mesh in place: select the meshes, give one number, and the polygon count drops. They differ in what that number promises — one guarantees the shape, the other guarantees the reduction.

Decimator by Tolerance

Decimator by Tolerance reduces each selected mesh as much as a deviation budget allows: you give a maximum deviation in mm (0.05 by default; the value is remembered for the next run), and each mesh is reduced to the heaviest percentage whose result still stays within that distance of the original surface. The shape is what is guaranteed — the face count is whatever falls out.

The search can take a moment on heavy meshes; press Esc to stop it, and the best result found so far is kept. The command line reports the triangle counts before and after, the percentage removed, and the largest deviation actually reached. Meshes that cannot lose anything within the budget are left unchanged. Quad meshes are triangulated by the reducer, so the “before” count can be higher than what the object properties showed.

Decimator by Percentage

Decimator by Percentage reduces each selected mesh by a straight percentage: you give the percentage of faces to remove (50 by default, from 1 to 99) and the reducer hits that count, even at the cost of shape fidelity. Heavy percentages will visibly facet the mesh — the reduction is what is guaranteed here, not the shape.

Use it when you know how much lighter the file must get; use the tolerance variant when the surface must stay true and you just want the mesh as light as that allows.