Surf Ice is a tool for surface rendering the cortex with overlays to illustrate tractography, network connections, anatomical atlases and statistical maps. While there are many alternatives, Surf Ice is easy to use and uses advances shaders to generate stunning images. It supports many popular mesh formats [3ds, ac3d, BrainVoyager (srf), ctm, Collada (dae), dfs, dxf, FreeSurfer (Asc, Srf, Curv, gcs, Pial, W), GIfTI (gii), gts, lwo, ms3d, mz3, nv, obj, off, ply, stl, vtk], connectome formats (edge/node) and tractography formats [bfloat, pdb, tck, trk, vtk].
BSD or BSD-style license: http://www.opensource.org/licenses/bsd-license.php
The BSD license is fairly permissive, placing few restrictions on the developer or user. As a developer, you may distribute source or binaries (with or without source code). As a tool user, you may modify and redistribute this tool or resource. If source code is distributed, a user may browse the source code to understand the tool's workings, modify the tool to better suit local needs, and share a modified version. If source code is not distributed, a user may still redistribute the tool as part of another package.