Decimate Software


System Requirements

Please refer to this document for the minimum computer system requirements.

When an object is digitized by a Cyberware 3D scanner, a dense mesh of surface measurements is made. The surface of a model may have a point defined every 0.5mm (0.02") both horizontally and vertically. While many features of the model may require this dense mesh of measurements and the corresponding high, large areas of the model that are smooth can probably be defined by far fewer measurements, perhaps 100 times fewer.

The scanned points are usually connected into a mesh of triangle-shaped polygons, with each measurement becoming a vertex shared by up to six polygons. Because the mesh might have several million polygons, workstation drawing performance while rendering models is limited by how many polygons the workstation can project, light and fill per second. Memory and disk storage can also impose limitations.

The polygon reduction software, Decimate, makes large models easier to work with by automatically reducing the number of polygons. Using a process called decimation, the software eliminates polygons only where their absence will not greatly affect the model's accuracy. The local geometry and topology of the model's surface is used to determine whether an individual vertex may be removed. When a vertex is removed, the software fills the resulting hole with larger polygons.

Decimate never creates new vertices; the vertices of the new model are a subset of the original vertices. This approach preserves the model's original structure, so that users can always map auxiliary data from the original model onto the decimated model. The auxiliary data includes surface normals (which indicates the model's 3D orientation at each point) and color texture data.

Preserving the ability to use the color texture data is especially important because the large polygons might be filled with high-resolution texture. The ability to overlay the color texture on the decimated model further enhances the model's realism, while allowing even greater reductions in the number of polygons.

Polygon Reduction

Reductions of up to 90 percent with only slight loss of detail are common. Software controls permit accurate control of the reduction process. Parameters that control the properties of the resulting mesh include percent reduction, preserving feature edges, size distribution of the polygons, and the number of iterations to make over the entire surface.

The process takes only a few minutes. You can immediately view the results of the reduction to determine if the parameters need to be altered to suit your needs.

Decimate accepts Cyberware image files and generates several popular modeling formats. The output consists of a list of vertices, polygons, surface normals and texture-map coordinates. Direct interfaces to products such as Alias/Wavefront, Softimage, 3D Studio, and Stereo Lithography are provided.


Decimation of Triangle Meshes, William J. Schroeder
Performance Driven Facial Animation, Lance Williams
Simplification of Objects Rendered by Polygonal Approximation, M.J. DeHaemer & Michael J. Zyda
Inputs: Cyberware Echo Files
Cyberware Ply Files
User Commands Via Keyboard
Outputs: Cyberware Ply