Seismic interpreters must be able to quickly scan through multiple volumes of data and combine information to get the optimal view of any geological feature of interest. Therefore, data processing and visualization are rigorously integrated in the OpendTect system. Visualization elements can be moved freely through data space to interactively analyze data from stored volumes, or data calculated on-the-fly. Attribute parameters can be inspected in a movie-style way. Visualization elements include slices (inlines, crosslines, 2WT), 2D seismic lines, horizons & faults , random lines and cubes. Volume-rendering and stereo viewing is supported for better understanding of the data and results.