Reduce the number of faces in a mesh

The Reduce feature lets you automatically reduce the number of polygons in a mesh by a percentage of the overall polygon count that you specify. The Reduce feature also attempts to retain the original shape as part of the reduction process.

Reducing the number of polygons is useful when you need to reduce the overall polygon count in a polygon mesh or reduce the number of polygons in a particular region of the mesh. For example, you may need to create a low resolution copy of a high resolution polygon model with a reduced polygon count for level of detail display purposes in an interactive video game. Another example would be to simplify a polygon data set of a detailed physical model that was 3D laser scanned.

Overall, polygon models that have been simplified will have less data and improved interactive performance when animated in the scene view.

The polygon reduction is controlled via a polyReduce node that gets created. This lets you experiment with the amount of blend reduction and can be removed altogether should you wish to return the polygon mesh to its original pre-reduced state.

To...	Do this
Reduce the number of faces in a mesh.	Select the faces you want to reduce, then choose Mesh > Reduce > .
Keep the current polygon mesh so you can compare the original and reduced versions as you change options.	In the Polygon Reduce Options window, turn on the Keep Original option. The reduced mesh will appear next to the original along the X axis.

To...

Do this

Reduce the number of faces in a mesh.

Select the faces you want to reduce, then choose Mesh > Reduce > .

Keep the current polygon mesh so you can compare the original and reduced versions as you change options.

In the Polygon Reduce Options window, turn on the Keep Original option.

The reduced mesh will appear next to the original along the X axis.

You can also use the Artisan paint feature to specify a region on the polygon mesh you want to have the polygons reduced. Painting a region for reduction using the Paint Reduce Weights Tool gives you finer control over the polygon reduction as well as blend between the areas where less reduction occurs.

To get finer control over which areas are reduced using the Paint Reduce Weights Tool

Select the faces you want to reduce.
Choose Mesh > Reduce > .
Set the general reduction percentage and turn on Keep Original, then click Reduce.
The reduced mesh appears next to the original along the X axis.
Choose Mesh > Paint Reduce Weights Tool.
Paint reduction values on the original polygon mesh.
Darker areas will be reduced more. Lighter areas will be kept as-is as much as possible.

As you paint on the original, the reduced version updates.

Notes on using the Reduce feature

You cannot paint reduce weights on the reduced version. You must use the Keep Original option and paint on the original object.
If you try to paint reduce weights on the reduced version, Maya will automatically select the original instead.
When you select faces to reduce (rather than reducing the entire mesh), faces bordering the selection may move or be reduced as well.
You can avoid this effect by extracting the polygons from the mesh before reducing them. Turn on the Preserve - Mesh Borders option so the extracted mesh can be reattached later.
When you are painting reduce weights, the Paint Attributes Tool’s default is to only update when you finish a stroke. This is because the reduce operation can take a noticeable amount of time on large meshes.
If you want the reduced version to update as you paint, choose Modify > Paint Attributes Tool > , open the Stroke section, and turn on Update Continuously.
Reduce Weights are a bias, not an absolute control. In some extreme cases polygons that you painted white but are not needed will still be reduced to preserve shape elsewhere.
Reduce works with quads and n-sided polygons, however, non-planar polygons can become deformed and may not reduce well.
The Keep Quads option can produce distorted results in some situations. When this occurs, reduce the Keep Quads slider value or increase the Triangle compactness option until you achieve a satisfactory result. (The Triangle compactness option affects the mesh reduction even if the mesh is comprised of all quad polygons).
If you are painting reduce weights and want to revert a region back to its original state, you can either undo your paint strokes or simply flood the mesh with black color.