In this paper a new direct volume-rendering method is presented for fast display of iso-surfaces. In order to reduce the data to be processed, the algorithm eliminates those voxels which are invisible from a specific domain of viewing directions. The remaining surface points are stored in an appropriate data structure optimized for fast shear-warp projection. The proposed data structure also supports the application of cutting planes in order to visualize the internal part of the volume as well. Unlike many other surface-oriented techniques, the presented method does not require any specialized hardware to achieve interactive frame rates,  thus it can be widely used in medical imaging applications even on low end hardware.