 The TARDIS on the cloud was achieved through a mix of fog on the studio floor and post @-@ production special effects . Director Saul Metzstein explained that it was difficult to achieve the desired look for the snowmen ; the first ones he likened to Zippy from Rainbow which was too " cute " of an appearance , and so the effects team created more menacing CGI faces . Clara 's introduction to the TARDIS introduced two novel effects for the show . The first was a single @-@ shot camera tracking from a few feet away from the TARDIS to its interior , with the implication of the TARDIS 's trans @-@ dimensional nature shown to the audience . In the following shot , the camera does a complete circle of the TARDIS console , an effect not seen since the early days of the show . Metzstein wanted to include this shot to further emphasize the " bigger on the inside than the outside " nature of the time machine . 
 The TARDIS on the cloud was achieved through a mix of fog on the studio floor and post @-@ production special effects . Director Saul Metzstein<a href='been_done' title='1'><mark></mark></a> explained that it was difficult to achieve the desired look for the snowmen ; the first ones he likened to Zippy from Rainbow which was too " cute " of an appearance , and so the effects team created more menacing CGI faces . Clara <a href='null_genetive' title='2'><mark>'s</mark></a>introduction to the TARDIS introduced two novel effects for the show . The first was a single @-@ shot camera tracking from a few feet away from the TARDIS to its interior , with the implication of the TARDIS <a href='null_genetive' title='3'><mark>'s</mark></a>trans @-@ dimensional nature shown to the audience . In the following shot , the camera <a href='uninflect' title='4'><mark>does</mark></a> a complete circle of the TARDIS console , an effect not seen since the early days of the show . Metzstein wanted to include this shot to further emphasize the " bigger on the inside than the outside " nature of the time machine . 
The TARDIS on the cloud was achieved thru a mix of fog on da studio floor and post @-@ production special effects . Director Saul Metzstein been explained that it was difficult to achieve tdadesired look fa the snowmen ; the first ones he likened to Zippy from Rainbow which was too " cute " of an appearance , and so the effects team created more menacing CGI faces . Clara  introduction to thdaARDIS introduced 2 novel effects for thedaow . The dast was a single @-@ shot camera tracking from a few feet away from the TdaIS to its interior , wid the implication of the TAdaS  trans @-@ dimensional nature shown to the audience . In the following shot , the camda do a complete circle of the TARDIS console , an effect not seen since the early days of the show . Metzstein wanted to include dis shot to further emphasize the " bigger on the insidaden the outsida" nature of the time mdaine .