The Normal Smoothing Featureimproves the appearance of curved meshes by blending the way light reflects from its faces.
For example, the torus below has normal smoothing on on the left side, and off on the right.

Apply this feature to the faces that make up a curved surface on your mesh: it can give greater realism.
Select the mesh with areas you’d like to smooth.
Create a new “Normal Smoothing” feature in the feature stack for that mesh. Place this feature below (after) any geometry changes in the stack, such as Move Vertices or Weld Vertices.
Select the faces you would like to include in the smoothing. There is no need to select faces that are flat next to each other, or at a sharp angle: the feature can confuse these sharp edges.
To see the feature applied, close the feature in the stack. Click anywhere on the feature header, such as to the left of the eye icon, to close the accordion: the caret symbol will rotate, the feature will close, and you’ll see the effect applied to the mesh.
To edit the feature, open the feature and change the collection of faces selected.
Normal Smoothing Feature Properties
Property | Options |
---|---|
Name |
Name the feature. Unique names for each feature is not required, but suggested. |
Smooth/ Unsmooth |
Change this toggle to specify if the selected faces should have the smoothing effect applied, or if the effect should be removed. |
Use
Primitives have normal smoothing.
Normal smoothing is applied by default to some faces of the curved primitive shapes (sphere, torus, cone, cylinder). This default smoothing can be removed. Add a normal smoothing feature to the primitive, select all
faces, flag them as “unsmooth”, and then collapse the feature to make it permanent.
Limit the faces you smooth.
While normal smoothing on a simple mesh is faster to calculate than a more complex mesh, it still adds work to the scene. Add normal smoothing only when necessary, and only to the faces that need it: those in the curved
areas of the mesh.
Technical Notes
How does normal smoothing work?
The meshes that represent objects in the 3D scene are a collection of flat polygons, or “faces”. To represent a curved surface, your mesh uses many small flat faces together to give the appearance of a curve.
To make that curved surface appear smoother and more realistic, two techniques are available:
adding to the geometry, or
adding a normal smoothing feature.
In the screenshots below, compare 3 spheres to see which looks the most realistic.


Consider the center sphere. This mesh has a few large, simple faces to represent a sphere. Each of those big faces reflects the light in a very different way from its neighbors. The difference from one face to the next is easy to see. The result: the sphere looks like a disco ball, and is not realistic.
Consider the left sphere. It solves the problem by adding geometry.
This mesh has 18 times as many faces. The smaller faces each reflect light in a way much closer to their neighbors, so it’s much harder to see the difference from one face to the next. The result: the sphere looks more realistic, but looking closely still shows the individual faces. And the mesh is more complicated, which can start to slow the performance of the scene.Now consider the right sphere. It solves the problem by adding a Normal Smoothing feature.
This mesh has just as many faces as the original center mesh, but the Normal Smoothing feature changes the way light reflects from those faces. Each face’s normal (the vector used to calculate lighting effects) is smoothed with the other normals around it. The result: a very realistic looking sphere! The right sphere looks smoother than the complex left sphere even though the geometry is 18 times simpler. The only drawback to vertex smoothing is the edge of the mesh, where the simple geometry can still be seen.