Game Development Reference
The idea behind this algorithm, introduced by Rossignac and Borrel, is to
encase the mesh inside a bounding box. This bounding box is divided into
an even array of cells. The cells are scanned to see if any vertices from
the original mesh are contained within the cell. In the resulting model, a
single vertex will be used for each cell that contains vertices from the
source model. Merging all the vertices that are found in a single cell
creates the resulting mesh. This algorithm has the benefit of speed but the
resulting models can be improved upon.
Figure 16.4 Using cell-based analysis.
The final option is to scan all the edges in the mesh using an algorithm to
determine the edge that will be least missed. Having decided on the edge
to remove, this is achieved by merging the end-points of this edge into a
single vertex. It is this approach that is used in Quadric Error Metric