3D discretized objects become more and more present in many applications for computer graphics. The need to store and transmit these data grows permanently. This paper introduces a new scheme of 3D object progressive transmission based on the coding of cone sections and balls from the medial axis and an optimization of the data transmission for a better scalability in terms of bit rates and quality. This representation of a voxelized object is a lossless approach and is very efficient for compression and progressive transmission, as shown in the results presented in this paper.