CGChannel has a great article by the folks at Intelligent Creatures on the technology they used and developed to create Rorschach’s mask in Watchmen.

We had successfully developed a technique to break up solid edges of any shape using noise generation. Although this project focused on the development of the Rorschach mask for the movie Watchmen (2009), this technique could be used on any solid-edge images, which ultimately increased our company’s knowledge base. Through extensive experiments with 2D particle simulations and Navier-Stokes simulation, we discovered the computational requirements were too expensive for us. Furthermore, these simulations were producing unpredictable and irreproducible results regardless of the high quality.

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