In some representative methods of triangle mesh compression

the connectivity is encoded using some kinds of traversal methods

the geometry is encoded by predicting the coordinates of each vertex with neighboring vertices along the traversal path.Their main drawback is the prediction only reduces the correlation between each vertex and its neighboring vertices in the traversal path.The coordinates of all vertices in a local spatial region have strong correlation.although these vertices are neighboring in space

they are usually not neighboring in the traversal path.Inspired by image compression standard JPEG

a novel block DCT geometry compression method is proposed.The input mesh is partitioned into many blocks.Given the fact that if all vertices in a block are ordered in traversal order

their coordinates distribute periodically

we use 1-dimentional DCT transform to reduce the correlation among all vertices in a block.The experimental results show the block DCT method has good geometry information compression performance.