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mesh_poly_reduce

About

Poly Reducer
Removed polygons from a mesh while maintaining the shape, textures and weights.
UI location Group: Mesh
Version 1.0 - 2006.02.07 Author(s) Campbell Barton
Blender 2.42 - present License GPL
Note(s) Included in Blender 2.42a - 2.46.


Executable information
File name mesh_poly_reduce.py


Links Included in Blender


Introduction

Poly Reducer

Mode: Edit Mode (Mesh)

Menu: Mesh → Scripts → Poly Reducer

Description

This tool can be used instead of blenders decimator modifier as a way to remove polygons from a mesh while keeping the original shape as much as possible.

Reasons you may want to use a polygon reducer are:

  • To make 3D Scanned data useable when rendering and editing.
  • Generate Level Of Detail models (LOD's), for games or simulation models.
  • To speed up render times.

Options

Poly Reduce is accessed from editmode and will operate on the entire mesh.

On activation a popup will be appear with the following options.

Poly Reduce
Scale the meshes poly count by this value.
Boundary Weight
Weight boundary verts by this scale. Zero disables boundary weighting.
A boundary vert is a vert that is not completely surrounded by faces. Some meshes have no boundary verts. eg. a cube has no boundary verts where a plane has all boundary verts.
Area Weight
Collapse edges affecting lower area faces first. Zero disables area weighting.
Triangulate
Convert quads to tris before reduction, for more choices of edges to collapse.

The advantage of triangulating is you have a larger set of edges to choose from when collapsing giving a higher quality result.

UV Coords
Interpolate UV Coords (if existing)
Vert Colors
Interpolate Vertex Colors (if existing)
Vert Weights
Interpolate Vertex Weights. (if existing)

Hints

Poly reducer has some advantages and disadvantages compared to Blenders decimator modifier, here are some pros and cons.

Pros

  • Higher quality resulting mesh.
  • Can operate on any mesh, will not throw errors if the mesh has odd face/edge/vert topology.
  • Options to control where polygons are removed.
  • Keeps materials assigned to faces.
  • Maintains UV Texture coordinates, Vertex colors, and Vertex Group Weights (used for bone weight painting) - This makes it very useful for game/realtime models.

Cons

  • Fairly Slow
  • Uses a lot of memory

Examples

famous cow.
Human with UV textures and bone weights from http://www.x-trusion.com
Heavily reduced workman http://www.x-trusion.com
Example of an 80% Reduction using a weight map for influencing the result- Original, Weight Map, Result of or an


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