We present an approach to compute the visual hulls of multiple people in real-time in the presence of occlusions. We prove that the resulting visual hulls are correct and minimal under occlusions. Our proposed algorithm runs completely on the GPU with framerates up to 50fps for multiple people using only one computer equipped with off-the-shelf hardware. We also compare runtimes for different graphic chips and show that our approach scales very well without additional effort. Comparison to other work shows that our algorithm is as fast as state-of-the-art technology. The resulting visual hulls can be the basis for a wide range of algorithms that require a robust voxel representation as input.