Mist can be used freely for both non-commercial and commercial purposes, see the licence agreement that accompanies the download. If you use Mist in connection with a scientific publication, please cite
Mist – A program package for visualization and characterization of 3D geometries. 2019. S. Barman, D. Bolin, C. Fager, T. Gebäck, N. Lorén, E. Olsson, H. Rootzén, and A. Särkkä.