Archive notice: This article was originally published on April 23, 2015. Links and embedded videos are preserved as part of the historical record.
Trixter was nominated in the “Best Postproduction” category.
The BBC has a strong programme. The British Broadcasting Corporation is not only responsible for the legendary TV series “Doctor Who”. In addition to documentaries, series such as “Luther”, “Misfits” and “Wolfblood” can also be viewed in this country. The award-winning youth series from the children’s division of the broadcaster, CBBC, focuses on the process of self-discovery during puberty using the metaphor of transformation – into a wolf. The Munich-based studio Trixter was responsible for set supervision and VFX.
DP spoke to supervisor Jan Stoltz from Trixter about rigging tricks, wolf actors and the English weather. The first season of the co-production between ZDF Entertainment and CBBC was broadcast on KiKa and ZDF respectively. It is now also available in stores. The second season was shot under the supervision of Jan’s colleague Robert Hoffmeister. The VFXs were also pitched to English companies, but Trixter was able to score points for the creature animation, not least because of the previous work on the mini-elephants for “Journey 2”.
“We were able to convince the CBBC that, despite the limitations of TV productions, we could make do with the budget and generate hairy creatures for the price,” says Jan Stoltz. After all, European TV budgets are a far cry from US features. “Here, a maximum of six-figure sums are possible to create effects for an entire season, i.e. for 13 episodes”. This also requires a different way of working. “With feature productions, there is often time for research and development. With TV jobs, you expect to pull a creature out of a hat that you can use immediately,” explains Stoltz. Nevertheless, working with deadlines was “not comfortable, but doable”, the supervisor recalls.
Filming took place between February and April 2012, with the film being handed in at the end of August. Trixter began pre-production of the wolves and effects during the shoot. Once the first material had been cut, Trixter got to work. The production time was a good four months, during which a total of 170 shots were edited. But the effects didn’t just include the wolves: the protagonists also have special abilities in human form that had to be visualised, such as their excellent sense of smell as visible scent plumes in the air. In addition to a fully digital transformation sequence, various full moons were – of course – also placed in the plates as matte paintings.
DP: Hello Jan, how was the collaboration with CBBC?
Jan Stoltz: Great. I was involved in the script work early on and was able to give tips on how to get as much wolf as possible for as little budget as possible. It wasn’t expected that instead of 20 agreed shots you’d suddenly have to deliver 40. Studios often try to squeeze the last bit out of a film, but this doesn’t necessarily lead to good quality in the end. With “Wolfblood”, on the other hand, the collaboration was on an equal footing and therefore a great motivation for everyone involved to get the best out of the effects shots.
DP: Do you often have to renegotiate?
Jan Stoltz: That’s hardly possible with German and European projects. The famous “change order” practically doesn’t exist here. Nevertheless, you know that budgets are limited. In US projects, you simply write down the additional costs if, for example, one wolf suddenly turns into 15. In Germany, it is usually assumed that the VFX company bears the risk, which can arise due to creative misjudgements or mishaps during filming. We try to achieve a fair balance in the budgets right from the start and communicate restrictions openly and at an early stage.
DP: How did you approach your wolves?
Jan Stoltz: First of all, we did a lot of classic research. We didn’t have to search long for good material: the BBC supported us with templates, as they also have a large documentary film section. There are also an endless number of films and photos of wolves on the Internet. We even found anatomical models of wolves without fur and then modelled the basic shape. A variant with modelled fur was of course created for approval by the customer.
DP: Were you also Pixar-like at the zoo?
Jan Stoltz (laughs): Yes, we took a trip to Hellabrunn Zoo and we also went to Poing Wildlife Park. That’s part of the research, of course.
DP: What colour concepts did you work with?
Jan Stoltz: The series is strongly characterised by earthy, natural tones. For example, autumn forests with rust-red leaves, the colours of Indian summer. The theme of the series is the contrast between the wolf as a wild, untamed animal in nature and humans living in an adapted world. The “Wolfsbloods” have to decide whether they want to enjoy freedom as wolves or follow a life of rules as humans. Each wolf character is based on the human actor in terms of fur colour and texture. For our original wolf “Lupus”, however, we first orientated ourselves on a real wolf’s fur and then later matched the fur colours of the variants with the desired colour concept.
DP: What was special about the rigging?
Jan Stoltz : As we were faced with the problem of producing variants of wolves that were to differ significantly in size and anatomical details, we had to come up with an inexpensive and effective method. The solution was hidden controls in the rig, which allowed us to dynamically scale, move or rotate almost every bone and almost every detail of the head. The advantage of this method is that the time-consuming work steps in the grooming and dynamic set-up of the skin only had to be carried out once. For the respective variant, the “original” rig was only provided with the corresponding scaling parameters of the character and the fur texture was exchanged.
DP: How much work would have been involved otherwise?
Jan Stoltz: Normally we would have had to model, rig and add fur to each individual anatomy, for example wider snouts and shoulders and a larger body for the male wolves. With this idea, which was developed specifically for production, it was practically always the same wolf that we were able to use to produce cost-effective variants.
DP: What software do you work with and how much effort was involved?
Jan Stoltz: We work with Maya, in which the models are created and rigged. We chose Shave and a Haircut as the fur tool for the first season of “Wolfblood”. We simulated the dynamic movement of the fur with Maya’s Cloth and later reduced it to a few guide hairs in order to minimise computing times. As with many previous productions, we used Renderman as our rendering software. However, the development of the fur shaders again required a lot of programming. Renderman is not necessarily known for “out of the box” solutions and every shader meant a new challenge. We wanted fur that reacted as realistically as possible to light. If an edge of light came from behind, it had to catch in the tips and the occlusion in the fur also had to work properly. Our shading TD Stefan Braun had already worked with Renderman for a few internal tests on the peculiarities of fur and was therefore able to provide us with impressive renderings very quickly.
DP: Were these tests enough?
Jan Stoltz: Not by a long shot. We had to continue developing the shaders right up to the end of production in order to speed up the calculation times and improve the quality of the shadows. We rendered over twenty layers for the fur alone: In addition to the usual passes such as Diffuse direct/indirect, Reflection, Specular, Shadow, Occlusion and Subsurface Scattering, there were also some special passes that allowed us to control the Depth of Field much more precisely than a conventional Z-pass would have allowed. There were also lots of ID passes that allowed us to isolate almost every part of the body later in the compositing process. A ramp from head to toe, for example, made it possible to adapt the wolves even more specifically to the different surfaces. Nuke was used as the compositing software, in which all the layers were put back together in predefined templates to create the finished wolf.
DP: How did you organise your workflow?
Jan Stoltz: We have a self-programmed, internal pipeline that automatically stores and versions data in the right places. This means that no work steps are overwritten – hardly any project works without this. However, we are already experimenting with new packages such as Shotgun and Katana for the next season of “Wolfblood”. This should significantly simplify the merging of assets and, of course, the entire lighting process.
DP: In “Wolfblood”, you handled the theme of transformation differently than we are used to from werewolf films, for example. Why is that?
Jan Stoltz : As “Wolfblood” is a youth series, there should be no transformation in the picture. Such an effect would have been too creepy and disgusting for the target group. In addition, there is always the problem of what happens to the clothes when an actor transforms. CBBC also wanted to get round this. So the transformation takes place via a flight into the eye of the respective performer, which initially turns wolf yellow. It continues with a short fun ride from the macro to the micro world: the veins on the retina fill with wolf’s blood. The blood cells change in the veins and the surface of the mitochondria changes in the cells. Finally, a DNA strand tenses – symbolising the power of the wolf. The ride then returns to the outside in just a few frames and the camera moves out of a wolf’s eye to show the transformed animal. The only exception is a 360-degree shot in the first season, which is almost a thousand frames long. An actor stands next to an already transformed wolf, the camera moves around the scene, the actor crouches down and disappears behind the wolf. When the camera releases him again, he is also transformed.
DP: Was a complete transformation discussed?
Jan Stoltz: Yes, it was. But it quickly became clear that a transformation in the picture would also be a completely different number in terms of budget. You can’t prepare or reuse anything: The actors are always in a different scene, the light varies, they wear different clothes – you would have had to set up the effect all over again. That was not an option. The inner transformation, on the other hand, was a pre-produced clip that we only had to adapt to the individual eyes later: on set, we only had to shoot one shot in which the camera flies towards the actor’s eye.
DP: Did you expect the series to be so successful?
Jan Stoltz: No, but the series seems to have struck a nerve. Personally, I thought that the whole wolf hype might be over after “Twilight”. But CBBC has found a great approach here with the realistic wolves. Because the wolves generally have little that is human about them. You can sense that something is going on with them: they don’t act irrationally like a real wild wolf. Nevertheless, their behaviour is always typical of wolves. This makes it a fantasy series, but one that moves back towards reality. What’s more, there is no better image for the theme of puberty than transformation, especially in the area of tension between school and freedom. It really is a clever concept. DP: How were you able to save on VFX shots during production? Jan Stoltz: For example, there are shots that show wolves moving quite far away. Our suggestion was to shoot with real wolfhounds. They were scenes at night and you could mainly see the silhouettes. This saved a few digital shots. As long as you don’t cut the real wolfhounds directly after the digital wolves, it works really well.
DP: What other tips do you have?
Jan Stoltz : You have to force the scriptwriters to think about when a digital character is necessary in the picture and when not. The same also applies to effects settings. In short: a character is only necessary if it drives the plot forward. Settings à la “The wolf stands there and looks” can be safely omitted. Look at animated films from Pixar. There’s hardly a shot where a character doesn’t contribute to the plot. Finally, when filming, there is the trick of elegantly keeping the character out of the picture. In this series, it was advantageous that the wolves are only waist-high from a kneeling perspective. You can therefore ensure that the wolf is not visible in the picture, but convey its presence by having the human actor look down, for example, or by filming a dialogue from the wolf’s perspective. Once the wolf has been established, you don’t need to show it in the picture for a while and can concentrate on the human actors. Only when the action actively continues with the wolf can it be seen in the picture again.
DP: These are basically very simple editing tricks.
Jan Stoltz: Exactly. For the viewer, a wolf that is constantly in the picture would perhaps be quite nice. But in terms of actual perception, it hardly makes a difference whether you can see the animal or just “feel” that it’s there all the time. Another option, however, is the overshoulder shot, in which you can only see some wolf fur out of focus in the foreground. This is more favourable than showing the wolf frontally with facial expressions in the frame.
DP: Were the scriptwriters happy to accept your suggestions?
Jan Stoltz: Yes, quite a lot. They weren’t even aware of a lot of things that could be easily and painlessly solved with editing. I rather initiated an interesting thought process that ultimately led to a denser plot. Some scenes even became a lot more exciting as a result.
DP: I saw in the trailer that there was a lot of night filming. How did you manage the lighting?
Jan Stoltz : Our excellent cameraman Tony Coldwell often only worked with two strong, artificial light sources for the series in order to achieve the most natural look possible. In order to still have drawings in the dark areas of the picture for compositing later on, it was agreed with him that he would expose one or two stops higher. I definitely needed to see the ground to know where the wolf was going. Tony shot with the Arri Alexa. Thanks to the preset lookups in the camera, I was able to see what the final image would look like on set.
DP: How did the shoot go in general?
Jan Stoltz : The shoot lasted three months. I was in Newcastle upon Tyne in the English county of Tyne and Wear for about four weeks for the VFX shots. I had a life-size stand-up of an already rendered wolf with me. It served as a rehearsal for the actors and as a reference for the cameraman, who was able to place the stand-up in the picture for the correct framing. Later, I worked with smaller tracking references or, for action sequences, I used a black pole with a green styrofoam ball attached to the front to control the direction of the actors’ gaze.
DP: How do you actually like working on set?
Jan Stoltz: The exciting thing about set supervision for me is when things don’t go as planned. In a TV production, you often have to reschedule and find a solution with the camera and director. Once we were no longer on schedule and some scenes had to be cancelled. The solution was for me to shoot the plates alone with a second unit. However, this only works if a production has confidence in the VFX studio and can react flexibly.
DP: So, are you happy with your work?
Jan Stoltz: I wasn’t entirely satisfied with some of the wolf close-ups in the end – simply because the wolves weren’t designed for close-ups in terms of budget. Apart from that, I think the whole team did an excellent job. I myself have rarely shot so many effects shots with CG characters on set in such a short time. On the shooting days, you’re pretty much whirled around to keep references in the frame and to record the camera data. We always filmed with two cameras at the same time and set up new shots every quarter of an hour. These 15 minutes were actually the time for the VFX supervisor to collect his data on set – that took some getting used to.
DP: Didn’t you have a colleague with you?
Jan Stoltz: I usually have assistants working on feature films, but because of the low TV budget, I was ultimately alone on set in England. The camera assistants helped me diligently to collate the data and during the breaks in shooting I compared my data with their documents. With a few tricks and a lot of team spirit, we made this great project possible.
DP: One more question about the shoot: how was the English weather?
Jan Stoltz: Mixed. We started in the woods at minus 5 degrees and sleet. That’s not really pleasant, especially for night shoots. At the end of March, however, it slowly became more spring-like. But when Robert Hoffmeister was on location for the second season in April, there was still two metres of fresh snow. He said that the sequence they shot there was more reminiscent of “Fargo”.
DP: Why are you no longer involved?
Jan Stoltz: The reason is “The 7th Dwarf” by Zipfelmützenfilm – the sequel to the “Seven Dwarfs” series as an animated film. I’m working on this project as animation director. The film will be released in cinemas in early 2014. It will be produced in English and will have a more international feel, especially in terms of humour … and perhaps not quite as dwarfish as the first two parts (laughs). Despite all this, I’m also supervising the second season of “Wolfblood” in an advisory capacity as animation supervisor, so I’m still very attached to the project.
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