Modeling · Intermediate

Smoothing group

A set of faces that shade as one smooth surface, with hard edges where sets meet

Also called Hard and soft edges, Sharp edges

What is a smoothing group?

A smoothing group is a set of faces that the renderer shades as one continuous, smooth surface. Where two groups meet, the shading breaks and you see a hard edge. It changes only how light falls across the faces, so a low-poly model can look rounded without extra geometry.

Think of it like this

It is like folding a sheet of paper. Soft-shaded areas are the gentle curves in the sheet; a group border is a crisp crease.

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.

How a smoothing group works

  1. 01You assign faces to a smoothing group, or mark the edges that should stay sharp.
  2. 02Inside a group, vertex normals are averaged so the shading blends smoothly.
  3. 03At group borders, normals split, so the shading changes abruptly.
  4. 04The shape stays the same; only the lighting across it changes.

Smoothing group vs subdivision surface

PropertySmoothing groupSubdivision surface
Adds geometryNoYes, many more faces
Changes the outlineNo, the edge stays facetedYes, the shape rounds off
CostAlmost freeHeavier mesh, slower viewport
Typical useGame models and hard-surface propsSmooth hero models and close-ups

Use smoothing groups to fix shading on light models; use subdivision when the silhouette itself needs to be rounder.

Where a smoothing group is used

  • Keeping crisp edges on low-poly game props
  • Getting clean normal map bakes
  • Moving models between apps without shading glitches

Beginner tip

Mark hard edges along the borders of your UV islands. Splitting the shading and the UVs in the same places gives cleaner normal map bakes.

Terms related to a smoothing group

Smoothing group FAQ

What are smoothing groups?
Groups of faces that shade as one smooth surface. Faces in the same group blend into each other; faces in different groups meet at a visible hard edge. They are common in 3ds Max and game pipelines.
How do smoothing groups in Blender work?
Blender uses sharp edges instead of numbered groups. Shade the object smooth by angle, then mark any extra edges sharp. On export, Blender can write the result as smoothing groups for apps that expect them.
Why do smoothing groups matter for baking?
A baker reads the low-poly model’s normals. Wrong smoothing causes gradients and dark seams in the baked normal map, while hard edges matched to UV seams give a clean bake.

Updated October 29, 2026 · Browse all 3D terms