Pro version includes all the features of the free version plus:

• Create ATiles object with one click from roof plane, geometry or spline.
• Cache mesh for speed. Store inside ATiles object generated geometry for viewport and render.
• Re-create mode. Rebuild objects without losing material or connection to other objects.
• More advanced tools – Volume, Path(beta) and Surface(beta) tools.
• Random transformations of the tiles – Rotate, Move and Scale.

Home Page - http://www.avizstudio.com/tools/atiles/