3Space Assistant from TGS
3Space Assistant lets you visualize, communicate and exchange 3D design information. It includes a feature to decimate large objects. This feature was originally released as a separate product called 3D decimator.

Home Page: http://www.tgs.com/

Action3D from Action3D Inc.
Lets you import .3ds and .x files and vary the model's LOD using a slider control (based upon progressive mesh technology). Uses DirectX and runs on Windows 98, Me, 2000, and XP. There is a free demo version and a full license sells for a low $50.00.

Home Page: http://www.action3d.net/

Balancer from Atangeo
Atangeo Balancer is a tool that allows you to find perfect balance between visual appearance and the number of polygons, quickly and easily. Balancer utilizes a high quality polygon reduction to preserve the visual appearance of your model. The model features, normals, texture coordinates, layer boundaries are all honored.

Home Page: http://www.atangeo.com/

Chisel from Trapezium
Chisel optimizes and validates VRML .wrl files. It includes a number of polygon reducing techniques including merging coplanar triangles, edge collapse, and triangle collapse. Chisel can also adjust numeric resolution of coordinates and remove unused coordinates.

Home Page: http://www.trapezium.com/
Documentation: http://www.trapezium.com/chiseldoc.htm

Geomagic Decimate from Raindrop Geomagic
Geomagic Studio is a CAD/CAE/CAM application that supports the Windows and Solaris platforms. It contains the Geomagic Decimate component that performs polygon reduction, preserving surface curvature and minimizes surface errors. Supported file formats include .obj, .3ds, .dxf, and .wrl. Geomagic Decimate sells for $295 (as of 8 Sept 2001).

Home Page: http://www.geomagic.com/products/decimate/

Polygon Cruncher from Mootools Software
A plugin for Lightwave, 3DS Max, and 3D Photo Browser that lets you reduce the number of polygons in your objects without affecting their appearance. Supports models with textures and vertex coloring. Also includes an OpenGL view and a batch processing feature.

Home Page: http://www.mootools.com/plugins/us/polygoncruncher/

Progressive Fans by Antonio Cortés Carrillo
Progressive Fans are a technology for progressive transmission and view-dependent simplification of manifold and non-manifold meshes. The application that builds the LODs uses Garland's quadric error metric and a volume heuristic.

Home Page: http://www.terra.es/personal3/atoniman/

Progressive Meshes Maya Plugin by Erik Pojar
Erik has written a Maya Plugin that implements a progressive mesh scheme using quadric error metrics. Additionaly, the user can supply custom weights (using Maya's Artisan interface) to control the aggressiveness of the simplification in different parts of the model. Full source code is provided.

Home Page: http://www.pojar.net./ProgressiveMesh/

ProgMesh from Paralelo Computação
ProgMesh is a Windows 9x/NT application for 3D polygon mesh simplification which supports the 3DStudio file format. A progressive file format is used allowing progressive downloads on the Internet to any level of detail. Texture maps are also downloaded progressively if in WLM format. The unregistered version only imports objects with less than 6000 polygons.

Binary: progmesh.exe (v1.2)
Register: http://www.paralelo.com.br/registro/register.htm
Home Page: http://www.paralelo.com.br/produtos/progmesh/progmesh.htm

Rational Reducer from Systems In Motion
Rational Reduced is a high-end polygon reduction tool with support for the follow file formats: .3ds, .dxf, .flt, .wrl. The product runs on Windows, IRIX, HP-UX, and Linux operating systems. Cost begins at $4,950 for 1 user and goes down to $3,710 for 7-10 users (as of 8 Sept 2001). A Software Development Kit is available to integrate this functionality in your own programs.

Home Page: http://www.rational-reducer.com/

RXpolyred from Realax
RXpolyred is a graphical polygon reduction tool available for SGI and Windows NT platforms. Materials, textures, surface-curvature and object hierarchy are all preserved, and RXpolyred can also calculate the switch-out-distance for each level of detail. RXpolyred is integrated in RXscene which supports .dxf, .iv, .flt, .wrl, .3ds, .obj, among others.

Home Page: http://www.realax.com/docs/html/products/urxplm.htm

Donya Simplygon
Simplygon is a versatile and powerful tool for optimizing 3d polygon mesh models, including high-quality polygon reduction and polygon repair-features. You can use Simplygon to automatically repair and reduce the size and complexity of your 3d polygon mesh models. Simplygon can be used for creating highly optimized level-of-detail (LOD) objects, and optimizing 3D models for simulations and rendering.

Home Page: http://www.simplygon.com/

TerraVision
TerraVision is 3D terrain visualization system that lets you browse massive terrain datasets over the Web. Multiple datasets from different servers around the Web can be streamed and fused into a single coherent representation of the planet. The software is freely available for noncommercial purposes on Windows, Linux, and Silicon Graphics platforms.

Home Page: http://www.tvgeo.com/
Data: http://www.tvgeo.com/download_datasets.shtml

Virtual Terrain Project (VTP)
The VTP site is maintained by Ben Discoe with the goal to foster the creation of tools for easily constructing any part of the real world in interactive, 3D digital form. This includes Open Source software for all stages of the terrain production process. To receive the source code, you must register (it's free) with Ben.

Home Page: http://www.vterrain.org/

VIZup Optimizer from Sergei Zawelsky.
VIZup is a product for reducing the complexity of your VRML 3D models. VIZup attempts to automatically preserve the visual quality as much as possible while users tune the polygon count to suit their needs. The author reports that this software uses custom genetic algorithms to achieve this goal.

Binary: vizup.exe (v1.0)
Home Page: http://www.vizup.com/