Mesh > Reduce

Reduces the number of polygons in a selected region of a polygon mesh, optionally taking into account UVs and vertex colors as it chooses which areas to reduce.

Reduce is useful when you need to lower the number of polygons in a particular region of a polygon mesh. 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.

You can also preserve the original vertex positions to minimize the overall shape change that occurs on the mesh as a result of the reduction.

You can optionally paint the amount of polygon reduction using the Mesh > Paint Reduce Weights Tool.

Mesh > Reduce >

Settings

Keep original: The original mesh is preserved for the purpose of using the paint weights features. See Mesh > Paint Reduce Weights Tool.

Reduction Method

Reduction method

Lets you reduce the number of polygons by specific values. Select from the following options:

NoteThe Reduce feature attempts to reach the specified number entered in the Vertex limit or Triangle limit field; however, if Preserve quads or other Feature Preservation options are enabled, the number of vertices or triangles in the reduced mesh may differ from the specified count.

Percentage: Lets you reduce the number of polygons by a percentage of the original polygon count using the Percentage slider.
Vertex limit: Lets you set the number of vertices in the output mesh using the Vetex limit field.
Triangle limit: Lets you set the number of triangles in the output mesh using the Triangle limit field.

Shape

Preserve quads

Maya attempts to maintain any existing quad topology on the mesh as it reduces. The slider range is between 0 and 1. The higher the value, the more quads in the final result. A value of 0 is equivalent to turning this option off. Reduce the slider value if the reduction results in an undesirable shape change.

Sharpness

Controls the balance between preserving small, sharp details versus larger shapes. At low values, details that are small and relative to the general shape of the object are more likely to be collapsed. At high values, they are more likely to be kept.

Symmetry type

Lets you select from the following options:

NotePreserve quads must be set to < 1.0 to use the Symmetry type options.

None: Turns symmetric reduction off. This is the default setting.
Automatic: Adds a symmetry plane to your output mesh so reduction is symmetric about the plane Maya selects. With this option selected, Maya decides which plane (XZ, XY, or YZ) is most symmetric. It also tries symmetry about the center of mass, which works well for regular shapes that aren't aligned to the X, Y, or Z axes.
Plane: Adds a symmetry plane to your output mesh so reduction is symmetric about the specified plane.

Symmetry tolerance

Controls the degree to which Maya looks to see if two points are symmetric across the symmetry plane, as a value of 0 to 1.

Symmetry plane

Specifies the axes for the symmetry plane. Select XZ, XY, or YZ when Symmetry type is set to Planar.

Feature Preservation

The Feature Preservation options help to preserve specific features during the reduction process. Use the sliders to control the priority given to preserving different edges and borders.

Mesh borders: Maya attempts to preserve the shape of polygon borders (edges that are not shared by other polygons) as it reduces.
TipSet Mesh borders to 1 to preserve the boundary of your original selection.
UV borders: Maya attempts to preserve the shape of UV borders as it reduces.

Turning this on can give unpredictable results if you have a lot of UV borders. Try sewing as many UV pieces together as possible before reducing.

NoteIf a polygonal surface has numerous UV seams on it and if the Mesh > Reduce operation is performed with UV borders turned on, there is a good chance the object will not reduce at all, since the reduction algorithm is attempting to maintain the UV borders (seams) that are on the object.
If you don’t mind losing your UV seams, turn off UV borders to successfully reduce your polygonal surface.
Color borders: Maya attempts to preserve the shape of color borders as it reduces.
Material borders: Maya attempts to preserve the shape of material borders as it reduces.
Hard edges: Maya attempts to preserve the shape of edges marked “hard” as it reduces.

You can set edges on a mesh to be hard or soft using Normals > Soften Edge or Normals > Harden Edge. Marking edges as “hard” can result in more shape retention than painting reduction weights.
Crease edges: Maya attempts to preserve the shape of edges that have crease values set as it reduces.
You can crease edges on a mesh using the Crease Tool. See Crease polygonal edges and vertices.

Advanced options

Vertex index map: Lets you export a vertex index map. To make relationships between vertices of your original mesh and output mesh, enter a name in the field to create a new color set. With the color set applied, you can look at a vertex in your output mesh and determine the index in the original mesh based on color. See Polygon color sets.

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