You use ENVI‑Met for free – legally – by downloading the official Demo version . It’s perfect for learning, prototyping, and academic work. Just remember the grid size and simulation time limits.
Typically 50 x 50 x 30 cells. To put that in perspective: if each cell is 2m x 2m x 2m, you can model a 100m x 100m area (about one city block) with 60m height. envi-met software free download