Resumo: This talk is about a simple new algorithm that performs fast and memory-efficient cell projection for (exact) rendering of unstructured datasets. The main idea of the "ZSweep" algorithm is very simple; it is based on sweeping the data with a plane parallel to the viewing plane, in order of increasing z, projecting the faces of cells that are incident to vertices as they are encountered by the sweep plane. The efficiency arises from the fact that the algorithm exploits the implicit (approximate) global ordering that z-ordering of the vertices induces on the cells that are incident of them. The algorithm projects cells by projecting each of their faces, with special care taken to avoid double projection of internal faces and to assure correctness in the projection order. The implementation is hardware-independent and handles datasets containing tetrahedral and/or hexahedral cells.