Smoke effects play a significant role in MIB3 and are featured in almost all of the 600 visual effects shots created by SPI for the film, including a memorable rocket launch sequence from Cape Canaveral in Florida. Creating computer generated (CG) smoke is a very labor-intensive process, requiring complex simulations that tie up expensive and valuable computer processing power. Theo Vandernoot is an effects supervisor at SPI and a longtime user of both Side Effects’ Houdini software and NVIDIA GPUs. He discovered that by using Houdini 12 (with improved GPU optimization) on an NVIDIA Maximus™-powered workstation, he could dramatically improve not only the speed of simulations by up to 10X, but also the quality of smoke generated in MIB3.

http://forums.creativecow.net/thread/267/3628 [forums.creativecow.net]

Also video making of
http://www.movieweb.com/movie/men-in-black-3/cape-canaveral-featurette [movieweb.com]

Nice!. Did SPI uses arnold to render houdini volumes? Not mantra? Why is that?

Just a wild guess.. SPI maintains their own branch of Arnold, so they are sitting right at the source.

Sony also has Svea, which is their own proprietary volume renderer.