Reply To: 3d droplet impact
For a basic introduction into OpenLB you can check out e.g. the userguide [pdf].
The provided examples commonly set up the geometry (meaning material numbers assigned to cells) in the prepareGeometry function. This is also the case for laminar/cylinder2d.
For a droplet impact you could start out e.g. by taking a look and modifying the freeSurface/fallingDrop(2,3)d examples (if free surface is a workable model for your application).