This paper addresses the problem of streaming progressively compressed 3-D models over lossy networks. Out of all encoded packets that can be transmitted, we intelligently choose a subset of packets to be transmitted using TCP in order to meet a distortion constraint, while transmitting the remaining packets using UDP to minimize the end-to-end delay. We call this new application-layer protocol 3TP (3-D models transport protocol). Experimental results show savings of 42% and 68% in delay time at packet-loss rates of 6% and 19%, respectively, compared to systems that do not optimize transmission according to the encoded bitstream content.