Modeling · Beginner

Decimation

Automatically cutting a mesh’s face count while keeping its shape

Also called Mesh simplification, Polygon reduction

What is decimation in 3D?

Decimation is an automatic way to cut the number of faces in a mesh while keeping its overall shape. The software merges and removes faces where they add the least detail, so a heavy scan or sculpt becomes light enough to load, share or print. It is fast but leaves messy triangles.

Think of it like this

It is like shortening an essay by cutting the least important sentences. The meaning survives, but the writing gets choppier.

Where it fits in a 3D project

  1. Create
  2. Surface
  3. Rig
  4. Animate
  5. Render
  6. Export

Create: Building the shape: modeling, sculpting, scanning or generating it.

Low poly6 facesMedium12 facesHigh poly40 faces
The same shape with more faces looks smoother and costs more to store and draw.

How decimation works

  1. 01You set a target, such as half the faces or a fixed count.
  2. 02The software ranks edges by how little the shape changes if they collapse.
  3. 03It collapses the cheapest edges first, merging their vertices.
  4. 04It stops at your target, leaving flat areas sparse and curved areas denser.

Decimation vs retopology

PropertyDecimationRetopology
HowAutomatic, from a ratio or countRebuilt by hand or with guided tools
ResultUneven trianglesClean quads that follow the form
TimeSecondsMinutes to hours
Best forStatic props, previews, printingCharacters that will be animated

Decimate when the model only has to look right and load fast; retopologize when it must bend, be rigged or be repainted.

Where decimation is used

Beginner tip

Decimate a copy, never your only original, and compare the two side by side. Stop lowering the ratio once the silhouette starts to change.

Terms related to decimation

Decimation FAQ

How do I reduce polygon count?
For a quick result, run a decimate tool and set a target ratio. For a model that will animate, retopologize it instead. Either way, bake fine detail into a normal map so the lighter mesh still looks detailed.
Does decimation ruin UVs?
It can. Decimation tries to keep UV seams, but stretching often appears, especially at low ratios. Decimating before you unwrap, or re-baking textures afterward, avoids most problems.
Is decimation good for 3D printing?
Often, yes. A printer only needs the outer shape, so a decimated scan prints fine if it stays watertight. Check it for holes afterward, because heavy reduction can open small gaps.

Updated October 29, 2026 · Browse all 3D terms