Visual effects supervisor Tom Turnbull sets up his motion-control unit in the elegantly decorated and vast foyer of the Mississauga Civic Center, which on this particular day doubles as a Philadelphia hotel convention room where The Lansmann Company will buy out Genetico, setting the scene for the medical thriller The Third Twin. Producer is Toronto-based Pebble Hut Productions for cbs.

The four-hour, $9.5-million miniseries set to air Nov. 9 and 11, is a fast-paced story starring Kelly McGillis (Top Gun) and Jason Gedrick (Backdraft) which deals with the possibility of splitting cells to create clones.

Aside from a little more physical contact and a slightly different finish, the screenplay written by Cindy Myer remains very close to Ken Follett’s best-selling novel of the same name.

‘The book is a page-turner and I tried to adapt that kind of style to the shooting,’ says director Tom McLoughlin. ‘When the movie starts out you think it is an evil twin movie, and then as it grows you realize there is a third twin.’

Just as the story evolves and becomes increasingly more bizarre, so did the atmosphere on-set: one scene had cinematographer Frank Tidy (Hoodlum) shooting hundreds of identical twins of all shapes, colors and sizes.

And although all the extras were authentic look-alikes, when it came to Gedrick’s character, the subject of the cloning experiment, all of his twins were fabricated using green screens, head replacements and some digital magic by Turnbull and his crew at Gajdecki Visual Effects.

In the past, Turnbull has used split screens to create the illusion of twins for an episode of Road to Avonlea, the Two pilot and The Prisoner of Zenda, Inc., a cable feature for Showtime filmed in Vancouver, but this is his first stab at twinning by head replacement.

Done digitally in post-production, the head replacement technique has been around for a few years and is a seemingly simple matter of placing the actor’s dome on someone else’s body.

The central challenge of The Third Twin was delivering interactive twinning, says Turnbull. ‘It’s fairly straightforward to do a split screen but as soon as you want the twins to touch let alone fight it’s a whole new level of difficulty.’

The head replacement technique was used in two shots, both of them involving tough, up-close mano a mano fight scenes, one actually featuring one twin putting a headlock on the other.

‘Often they use masks, which is okay for a wide shot, but if you really want to get in there tight and do something more interesting, you can digitally replace faces, arms, heads,’ says Turnbull. ‘Some of the best shots come out of doing it this way.’

The shots are created with two passes, shot as lock-offs, with no camera movement; one featuring Gedrick fighting against a stunt double, then another shot reversing the roles, with actor and stunt double fighting on the flip side of the frame. Heads are optically removed and the appropriate head is ‘painstakingly married to the scene in post,’ says Turnbull, using John Gajdecki Visual Effects’ Flame compositing system. ‘It’s a fairly brute-force approach,’ he says, ‘but digital technology combined with the skill of the artist allows you to do it.’

Turnbull says the person who makes the biggest difference is the actor. ‘If he is really tight technically it makes a big difference and Gedrick made the process work effectively. Also having a director that is on top of the concept and a good double makes a difference.’

Motion control is used as a tool to make the shots more believable and interactive while keeping everything moving at a steady pace.

There are a total of four motion-control shots in the miniseries which add camera movement to traditional split-screen scenes, including one which features three ‘Jasons’ appearing simultaneously.

The scene required three camera passes and Turnbull says the challenge in creating such scenes is getting timing perfect so in the end twins are looking at twins and all elements work together. Motion-control shots were created with Gajdecki’s in-house system.

‘The trick to making it work well in a motion-control shot is to make the timing of the eye lines and the timing of the moves of the actors sync up nicely with the different passes,’ say Turnbull.

The production side of Third Twin’s effects required about four people and an additional four will likely work on the post side, all handled in Flame.

In shooting the miniseries McLoughlin wanted to create as much interactivity between the twins as possible, which for him meant the use of stunt doubles, and for Turnbull involved numerous elaborate and creative blocking moves allowing for as much physical interaction as possible.

After working with Gajdecki several years ago and seeing him make reindeers fly and heads explode, producer Christine Sacani says when it came to cloning, there was no one else she would have used.

As for Toronto as a location, Sacani sees the city as very ‘film friendly,’ and says that while they once filmed here for the tax breaks and dollar value, today it’s the enthusiastic Canadian crews that bring them back.