Sherlock fan John Smith has unveiled a mind-blowing unofficial trailer for the detective drama’s new season.

The first of three new episodes began filming in Cardiff on Monday.

> Here’s everything we know about Season 4 so far.

Watch the teaser…

Smith reveals on YouTube: “The project took about fourteen months from start to finish, and would have taken about seven months to render on an average home computer (I ended up using Mental Ray on a Render Farm) Custom practical elements were shot against greenscreen and composited into the 3D scene to give it more movement – from blowing leaves to torn fabric to falling debris to the passing cars in the background.

He explained: “‘Action Essentials 2’ fire and smoke assets added that extra sense of realism, along with a few floating particles and the odd raindrop. ‘Optical Flares’ was used for each of the lights (as well as some off-screen to add a sense of a wider world), and it was all brought together with a few natural light-leaks to give the illumination an organic feel.”

Watch a VFX breakdown…

Find out more about John Smith’s incredible VFX work on his Facebook page.

> Buy the complete Season 1-3 boxset on Amazon.

> Buy ‘The Abominable Bride’ special on DVD on Amazon.

Are you looking forward to Season 4? Let us know below…