#SWATH Article + Clip: "Visual Effects Secrets"

Mirror, mirror on the wall, is Rupert Sanders’ retelling of the classic fable, “Snow White and the Huntsman,” the slickest of them all? Indeed ... it is all that and a bag of poisoned apple chips.
In one of the film’s signature scenes, Snow White (Kristen Stewart) and The Huntsman (Chris Hemsworth) confront a hulking Troll with gnarled, wood-like skin.
The Troll was added digitally after principal photography by effects wizards at Rhythm & Hues. To provide the actors with references on set, a fishing pole was used for an eye-line, and water explosions were set off to simulate the monster’s pounding attacks.
And what Snow White tale would be complete without a magic mirror?
When Evil Queen Ravenna (Charlize Theron) consults her looking glass, it transforms into a liquidy cloaked figure.
Effects studio The Mill crafted the effect with a fluid simulation that allowed this “Mirror Man” to dribble down stairs and slide across floors.
To give Theron a reference on set, a metal structure was crafted with a camera in its “chest.” This nifty trick allowed Theron’s “reflection” to be captured and later added to the digital model.

– Scott Broock 
TheDaily