Paraview - ParaView is an open-source, multi-platform application designed to visualize data sets of size...
Gmsh - Gmsh is a 3D finite element grid generator with a build-in CAD engine and post-processor.
VisIt - VisIt is an Open Source, interactive, scalable, visualization, animation and analysis tool.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Mayavi - Mayavi seeks to provide easy and interactive visualization of 3-D data. It offers:
GGobi - Data visualization and exploration