yt is an open-source, permissively-licensed python package for analyzing and visualizing volumetric data.
yt supports structured, variable-resolution meshes, unstructured meshes, and discrete or sampled data such as particles. Focused on driving physically-meaningful inquiry, yt has been applied in domains such as astrophysics, seismology, nuclear engineering, molecular dynamics, and oceanography
neuroglancer > Neuroglancer is a WebGL-based viewer for volumetric data. It is capable of > displaying arbitrary (non axis-aligned) cross-sectional views of > volumetric data, as well as 3-D meshes and line-segment based models > (skeletons).
Meshroom is a free, open-source 3D Reconstruction Software based on the AliceVision framework.