Nowadays, multidimentional modeling and visualisation of geological data permit fundamentaladvances in Earth Sciences. However, as numerous commercial applications devoted to suchmodeling are either expensive or unable to manipulate all available data, open-sourcesoftware is a noteworthy alternative. Using these software though requires combining several applications, applets and libraries at different stages of data processing and visualisation (e.g., GRASS GIS, R, MeshLab, Paraview). The most advanced of these applications – the GRASS GIS – except standard GIS (2D, 2,5D) funcionalities permits manipulation of true 3D and 4D data in both raster and vector formats (e.g., as raster3D-voxel, Vector3D-TIN,mesh, face). These allow construction of 3D geologic models (geologic horizons, solids, faults,thrusts, etc.), based on 2D cartographic data and 3D well and geophysical data. Visualisationof such models is easiestin Paraview (www.paraview.org), which moreover contains varioustools for modification of data according to the end-user's needs. MeshLab is another data modification and visualisation program purposed to work with meshes. R is softwareenvironment for statistical computing, some modules are very useful for geostatistic. There isno excange data problem between programs becouse, usually the OpenSource programs usestandard data formats.