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The optional second input’s polygons represent feature edges. The optional third input’s polygons may be used as a reference. The second and third inputs are matched to the first input mesh by point numbers.
The methods to reduce polygonal models are:
A percentage of their former size
A specific number of polys (within a few)
According to distance from a camera
A specific list of edges to collapse
Note that as it uses a triangular mesh internally, the polygon counts all refer to a count in triangles.
A second input for feature edges is provided. A third input for reference is provided.
To get a uniform distribution of polygons you may need to turn up the Equalize edges parameter beyond the 0-1 range, to 10 or even 100.
Select the object whose polygons you want to reduce.
Click the PolyReduce tool on the Polygon tab.
Select the crease edges, if any, and press Enter when finished.
This tool requires a triangular mesh, which may increase the initial polygon count.
The polygons which will be candidates for simplification. Other polygons which share points with these might also be affected.
Which polygons are feature edges. You may specify an edge group here as well as individual edges, primitives or a primitive group.
You must connect something to the second input for this parameter to work.
Choose reduction level with a percentage.
Number of Polygons
Specify a desired number of polygons.
Reduce polygons based on distance to an object.
Collapse specific edges in an optimal fashion.
Controls how new points are found when an edge collapses. An optimizaiton of 1 will try to place the point to minimize the change to the surface. A value of 0 will place the point in the midpoint of the edge.
Without any constraints, the edges of planar surfaces can erode. This controls a bias which penalizes such erosion.
The amount of penalty to add to the feature edges being eroded.
You may have to increase this value to see results.
This bias penalizes the removal of long edges. It tends to reduce high aspect ratio triangles at the expense of more uniform reduction.
This bias uses the point attribute "weight" to control the polygon reduction. Points with a larger weight value will be more resistant to collapse and better preserve the original surface geometry.
This biases against vertices which have a large or small number of connected edges. Adding a topological weight results in a more uniform triangular mesh topology which can result in better tristripping.
Prevent Mesh Inversion
When enabled, each reduction is tested to see if it would flip a triangle normal. While incurring a slight cost, the results are almost always worth it.
Converts the mesh to triangles before reduction. This gives more freedom in how the mesh can be reduced.
This prohibits the removal of any edge that occurs at the boundary of the polygons. This ensures no cracks develop with unreduced areas.
Use Original Points
When it collapses edges, it will use one of the two original points instead of finding the optimal interior point.
When enabled, the specified frame is used as a reference for the polygon reduction process. The input geometry should be topologically invariant.
Use Reference Input
When enabled, the third input is used as the reference geometry on which the polygon reduction process is based. The input and reference geometries should be topologically equivalent.
The reference geometry is first processed by the polygon reduction algorithm. The results of which are then applied to the input geometry.
Animating input geometry that is fed through the PolyReduce SOP will exhibit flickering, since the PolyReduce SOP will give different results for different edge lengths. To avoid the flickering, turn on the options "Frame" and "Use Reference Input". Using static geometry will not produce flickering. The "Frame" option specifies that a particular frame be used either from the input or the reference geometry.