An algorithm for the progressive transmission of three-dimensional models over the internet

Abstract

The Internet has become a popular platform for the delivery, visualization, and sharing of spatial datasets. However, the narrow network bandwidth greatly limits the delivery of spatial datasets. Users have to wait for quite a long time when they download datasets from a remote server. The users might interrupt a transmission procedure because of long waits. Progressive transmission is a promising solution for the performance improvement of transmission. The goal of a progressive transmission is to deliver a coarser resolution dataset to show users an approximate impression in a short time. Moreover, the resolution of the dataset is gradually enriched during the procedure of transmission until the whole dataset is downloaded. This paper proposes an algorithm for the progressive transmission of triangle based three-dimensional (3D) models (e.g. terrains) over the internet. The kernel of the algorithm encompasses three parts (i) the multi-resolution representation of 3D models; (ii) 3D data streams for the transmission; and (iii) the reconstruction of 3D models. The algorithm firstly decomposes a full-resolution 3D model with multi-resolution representations on a server side, which generates a crude 3D model plus many details. The crude 3D model gives clients an approximate impression, and the details are progressively transmitted to reconstruct the original 3D model. The algorithm was implemented and integrated in a client/server architecture prototype. Experiments were undertaken to evaluate the performance of the algorithm. The experimental results demonstrate that the algorithm is able to improve the transmission efficiencies of 3D models over the internet greatly.