Definition:The decimation method in CPM (Compressed Progressive Meshes)[1]is “edge collapsing”, which collapses the two ending points of the selected edge to the midpoint.
CPM collects “edge collapsing” into batches to achieve a high compression rate. The connectivity information of the removed vertex is encoded with the identifiers of the two cut-edges. CPM applies Butterfly subdivision scheme to predict the displacement of the new vertex. The error between the predicted and the original positions is stored as the geometric data in each batch. The amortized connectivity encoding takes 7.2 bits, while the geometry encoding takes 15.4 bits per vertex.
Figure 1 shows the base mesh M0 and the mesh M1 constructed with CPM. From M1 to M0, two edges A’A’’ and F’F’’ are collapsed to the midpoints A and F, respectively.
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References
1.
R. Pajarola and J. Rossignac, “Compressed progressive meshes”, IEEE Transactions on Visualization and Computer Graphics, Vol. 6, pp. 79–93.Google Scholar
