“For the long-awaited return, we needed to drop Claire suddenly right in amongst the hustle and bustle—and grime—of 18th Century Edinburgh, into the famous and well-recognized 'Royal Mile’.

The real place being such a busy and rather confined street in modern Edinburgh, it was entirely impractical to actually stage there, especially for scenes playing over multiple episodes that would have required cleaning up shots to remove modern artefacts. The decision was made to digitally recreate the street as a 3D CG environment that we could move our cameras around in as we pleased and generally have much more freedom during filming. The cast and some appropriate crowd were filmed at the studio on a short cobbled section of street, created especially. This was almost wholly, apart from the immediate street surface and a couple of small stone-textured flats (for close-up coverage) a green screen environment, with green screens positioned as required for each framing.

Using a process called photogrammetry, many thousands of detailed photographs were taken of the real location and surrounding streets, from multiple angles. Specialized software is then used to derive and calculate a 3D geometry or form.

Cleaned of modern artefacts like signage or lights, the photos going through the photogrammetry process, are blended into large textures that can be effectively ‘projected’ onto the derived geometry. Taking note of extensive historical research by the Art Department, we also added some components to upper floors that for the most part, no longer exist to photograph, and replaced all windows.

The result is convincing 3D photo-real buildings that we can view from almost any angle.”