MEDVIS 3D, a system for visualization, segmentation of medical image data and simulation of blood flow through 3D structures, is the result of several research projects of the RISC Software GmbH – Research Unit Medical-Informatics, together with the Johannes Kepler Universität Linz, the Kepler Universitätsklinikum NeuromedCampus Linz (formerly OÖ Gesundheits- und Spitals AG) and the Kepler Universitätsklinikum MedCampus Linz (formerly General Hospital Linz). The project goals were the development and extension of a clinical software tool for 3D visualization, measurement und simulation of biological structures on the basis of medical imaging data from X-ray angiography, MRT and CT. We have accomplished to develop a software tool that is able to provide all means to simulate the blood flow through intracranial aneurysms. The software is able to reconstruct the 3D blood volume, generate a simulation mesh and run a complete CFD/CSD simulation of the blood flow with fluid-structure interaction using state-of-the-art CPU/GPU hardware acceleration technologies. The (intermediate) results can be directly visualized in our software. We now offer a free version of MEDVIS 3D that is capable of reading arbitrary DICOM images and visualize the contained volume information in 3D.