This demonstration of rolling clouds with the Cebas Pyrocluster 3 plugin for 3DS Max is an animated version of a scene that comes with Pyrocluster. The 3DS Max document is called '[samples location]/pyro standard/cloud_05_cumulus.max'.

Over a period of 10 seconds the following settings were animated: shape radius from 100 to 225, noise size from 80 to 250 (to prevent the clouds from looking smaller/more detailed with each frame) and phase from 0 to 1.