In After Effects, the branch, background and CG butterfly were combined. "We used a lens blur with a Depth pass for the depth of field," adds Hill. "The Shadow passes were important to help ground the butterfly on the branch." To complete the shot, a camera move was added to give it a more natural, hand-held feel.
A second Springwatch spot presents us with a caterpillar crawling along a branch, before reaching up to sniff a flower, forming the shape of the '2' with its body. The creature's movements required a full rig with bones and IK, with enough flexibility to animate and twist its body into the required shape. "It was tricky getting him to crawl correctly and maintain the '2' shape throughout," says Hill. "Especially when he rears up to smell the flower. We had quite a number of morph targets."
For this shot, only the caterpillar is a 3D mesh; everything else is a 2.5D element based on photos shot on location and layered in After Effects. The flower was broken down into three or four separate pieces, enabling the team to add some subtle movement. The branch image is a static plane, although Hill explains that they modeled a version of the branch from the photo, which was then used in Cinema 4D to catch the caterpillar shadows. "We added extra 2D shadows as and when needed to help ground the body and when the caterpillar interacts with the flower," he adds. Again an HDRI was used in conjunction with an area light, and outputs included Shadow, Hair, GI, Specular, AO, Diffuse and Motion Vector passes.
"The caterpillar was a fairly tricky composite, especially for the shadows," comments Hill. "The head movement in front of and behind the flower was very tricky to get a seamless transition from front to rear, and then head inside the flower. We made the petals semi-transparent to help with the composite."
The final spot is a generic ident for the channel, featuring Nigella Lawson mixing some chocolate intended for a cake. However, when her back is turned the '2'-shaped spatula guzzles it up, becoming bloated in the process.
As expected, the liquid simulation was achieved with Next Limit's RealFlow, although Hill admits that the scene took a while to perfect. "The chocolate consistency had to be right to make it behave realistically," he says, "but needed to move in a non-real way to get the chocolate to drain away quickly enough for the idea to come across and fit within the allotted air time requirements. We used Kill Daemons and various other Attractor, Spline and Vortex Daemons to create the main chocolate movement and drain."
With the simulation sorted, they generated meshes with vertex maps within RealFlow, saved as standard BIN files. These were then imported into Cinema 4D using the latest RF plugins to keep things as stable as possible rather then meshing at rendertime using the RealFlow Render Kit.