VTK applications are largely constructed by connecting vtkAlgorithms together. Each algorithm (a.k.a. filter) inspects the dataset or datasets it is given and produces some derived data for the algorithm (or algorithms) connected to it. The connected set of filters forms a data-flow network. VTK uses reference counting heavily to eliminate redundant memory consumption and timestamps in the demand-driven network to eliminate redundant computation. Algorithms are strongly type-checked to enforce compatible filter connectivity.


VisIt is an Open Source, interactive, scalable, visualization, animation and analysis tool. From Unix, Windows or Mac workstations, users can interactively visualize and analyze data ranging in scale from small (<101 core) desktop-sized projects to large (>105 core) leadership-class computing facility simulation campaigns.


ParaView is an open-source, multi-platform data analysis and visualization application. ParaView users can quickly build visualizations to analyze their data using qualitative and quantitative techniques. The data exploration can be done interactively in 3D or programmatically using ParaView’s batch processing capabilities.