For the movie Cursed, Frantic Films was required to insert simulated
wispy smoke whenever the werewolves came in contact with silver.
Image © 2005 Dimension Films.

For several scenes in Cursed, Wes Craven's latest film, Frantic Films was required, during post-production, to insert wispy smoke whenever the werewolves touched silver.  Simple particle systems failed to capture the characteristic motion of wispy smoke, while existing smoke simulators generally produced smoke of a diffuse nature, more appropriate for explosions or large flames than cigarette or incense smoke. This sketch describes our implementation of a flexible, artist-friendly smoke simulator capable of producing realistic wispy smoke for a production environment.  In brief:

Our method is based on the Navier-Stoke fluid simulation method introduced in Foster and Fedkiw [2001] and on the particulate-combustion model introduced in Feldman et al [2003].

In order to accelerate our simulations, we implemented a moving bounds approach, as in Rasmussen et al. [2004], which allowed us to simulate a smaller region. We then combined this with a variation on that paper’s grid-sourcing method.

In order to provide the maximum degree of control and flexibility to artists, we implemented a variety of mechanisms within a 3DS Max plug-in.

As for rendering, in our simple lighting and rendering model, smoke particles were rendered directly to an initially empty accumulation buffer accounting for camera and fluid motion blur, as well as particle ages.

 

Batty, C and B. Houston. (2005) "The Visual Simulation of Wispy Smoke."  Proceedings of the SIGGRAPH 2005 Conference on Sketches & Applications. ACM Press. [PDF]

@inproceedings{
   author = {Christopher Batty and Ben Houston},
   title = {The Visual Simulation of Wispy Smoke},
   booktitle = {Proceedings of the SIGGRAPH 2005 Conference on
       Sketches \& Applications},
   year = {2005},
   location = {Los Angeles, California},
   publisher = {ACM Press},
   }