The cult

Tremors is one of those franchises that haven’t lost their appeal through the years. Released in 1990, the first one starred Kevin Bacon and established a new genre - “horrormedy” - which attracted quite a big fan base. Even though each of the three sequels was produced with a smaller budget than the previous one, the production quality and the final result didn’t suffer and the fan base continued to grow. Part of the reason for that was that the creative team from the original movie remained behind all the sequels and even more so because Michael Gross (who played Burt Gummer) starred in all of those movies. For anyone familiar with the Tremors series, Burt’s character and his sassy humor are trademarks of the franchise.

Fans of the Tremors series should get ready for a great new installment, because eleven years after Tremors 4, Burt Gummer is back again, this time with a new sidekick (comedian Jamie Kennedy) and they are going to Africa. The reason is a no surprise – huge Graboids and Assblasters are spotted there. And as they say, “Everything is bigger in Africa”.

Creature (Re)Design

Victor – the VFX producer and the creative force behind the creature design explains: “When we were approached by Universal Pictures about this project I knew that we would have to take advantage of our full stack of CG capabilities and revamp all creatures, not only to make them bigger, tougher and more vicious, but to somehow bring them into 2015.” Cinemotion began working on the creature designs long before the film was even in pre-production. “I love when we have more time to think over the movie before it is shot and before it is even started. It is much a more relaxed way of working on concept design or coming up with ideas for the VFX or other aspects of the movie. Usually when you work on low- to middle-budget productions you don’t have this luxury, just because nobody is ready to pay for it. Over the years, I have found that working on movies in this way is time very well spent and it does pay back, because a great concept is everything. We are so fortunate that our clients have trusted us with the challenging task of concept design for most of the movies we have worked on. That has allowed us to connect with the creatures, get inspired by the great designs and, of course, start modeling, rigging and testing long before the final plates start arriving at our door. One thing I have learned over the years is that without great character design nothing else matters. You can do an incredible job in look development, in lighting and rendering, the animation can be perfect, but all this is useless if the creature looks bad.”

Graboids

“When we began working on the concept, the Graboid design was our first task. The Graboid is one of the most iconic creatures in movie history and I love the way they look, but they were designed in 1990 and they were created so they could be built and controlled as animatronic puppets. All of that called for some compromises because of the practical limitations of working with physical models. In Tremors 5 for the first time all of the creatures would be CG, and we wanted to use all the freedom this allowed us. At the same time the CG approach was a huge risk for the producers, because both the core of the Tremors fan base and the original creators were so addicted to the original look of the movies and somehow nobody could imagine a full CG Tremors. 20 years ago, when Phill Tippett’s studio (probably one of the best CG creature effects studio in the world at that time) created the Shriekers for Tremors 2 using CG, they looked so terrible that nobody wanted to take on that challenge again. This was a huge responsibility for us, and the only way to be true to the fans was to deliver CG creatures of exceptional quality, perfectly integrated into the live action environment with all the dust, dirt and gore that was in the previous movies.”

Just as Amalgamed Dynamics did 25 years ago in the practical and special effects domain, we had to use the full arsenal of CG techniques at our disposal. Part of the backstory and a focal point of our redesign was the fact that those creatures are in South Africa – a completely different branch of Graboids. Like many other animals, the African Graboids were supposed to be older and more evolved, faster and more agile. During the preproduction I visited a paleontological institute in Johannesburg, and had the chance to speak with Adam Yates, one of the most respected paleontologists in the world. He told me about a very interesting termite that still lives in the areas and is able to burrow through rock. First it spits formic acid, melting the rock, and then using his magnesium mandibles to dig through it. Fascinated by the fact that there are actually creatures like the Graboids, we just took the creative license to make them about 7000 times bigger and able to dig 2000 times faster. Magnesium is black, so we changed the Graboid’s mandibles to black. We changed their bodies to a corkscrew shape, because that seemed like the only way this creature could travel underground without displacing huge volumes of dirt. We put shock- sensing organs on top of its head, and two small dents in the place of eyes since a subterranean creature does not need to see. The viewer always needs to see eyes in a creature, otherwise it is too anonymous and not as terrifying. The director had hoped to give the creatures a more vibrant look, since people think of everything in Africa as brighter and more colorful. But as an underground creature, the Graboid had to look gritty, dirty and natural.

Assblasters

“For the Assblaster I wanted something different than what we had in the originals. To be honest, I hated the original Assblaster design and I thought that it could be greatly improved. My thought was to make it more vicious, more agile and to make it look different from everything else. Here, as always, the devil was in the details: the turbine at the end of its body holding flammable gas; the two curved bones that ignite the flames from that same turbine; the burned-out scales left from hundreds of fire blasts; the small weak wings used for gliding; the way the wings fold invisibly into the body; and of course, the grotesque mouth. One of my aims was to bring the Assblaster much closer in appearance to the Graboids, because they are directly related. Graboids are hatched from Assblaster’s eggs and they should look more like each other than they had previously.”

Grabbers

The Grabbers in this movie have a unique feature – they are able to travel separately from the mother Graboid. This called for a slight redesign so they have enough features to be able to dig through the ground and slide on top of the ground. The production team have built physical model Grabbers to be used in many of the shots, but in the final edit all the shots in the movie used a CG version of the Grabber.

The Modeling Phase

Once the design process was finished and all of the concepts were approved, we started the modeling. “I knew that it would be crucial for the movie that all creatures look as real as possible. The fans were used to seeing physical effects in Tremors movies, and we wanted the transition to full CG creatures to be as smooth as possible” says Stiliyan, head of modeling. “I took the liberty of changing quite a lot what I have got from the original concept art, because I knew that we could add a lot at that stage of the process.” Many small details and nice design features were added at that stage, which greatly improved the overall look of the creatures.

Rigging and Character Setup

Because of the very complex models we ended up with, the rigging of the creatures - especially the Assblasters - was a huge challenge. “From the beginning it was clear that we would be in some unexplored territory with this project. Neither the animators nor the rigging TDs were sure how to approach the task, or what controls would be optimal for these creatures” says Pavel, TD character supervisor. “For that reason, it was clear that there would be a lot of back and forth and many more iterations in the process compared to some of the other projects we have done. The only way to do that was to automate the rigging process as much as possible. This was a great opportunity for me to finish the auto-rigging system I had been developing for quite some time. It allowed us to rebuild the rigs in a fraction of the time, after every design or model change. This was a huge timesaver saving weeks of work”, adds Pavel.

Look Development

To develop the look of the creatures, we used our real-time 8xGPU and Vray RT, which saved a lot of time and allowed us to see very complex shades changing in real-time with subsurface scattering, motion blur, and everything else happening instantaneously. For the Graboid we added many layers of dirt and mud on top of the creature so it would look and feel like an underground creature. This added even more complexity to its already quite dense look. “One thing I really liked with the Assblasters was how we covered the back of the creature with a charcoal material that gradually fades to its original colors at the front, because of the hundreds of fiery explosions coming from its tail,” explains Nikolay, head of lighting and look development. “For the lighting rigs we developed the so-called ‘extended HDRI maps’ which used additional lighting sources on top of the HDRI 360 maps acquired from set. This was done to give more ‘punch’ to the lighting and to give more life-like dynamics to the renders than what the pure HDRI approach is able to deliver.”

Creature Animation

Much of the heavy lifting for the project was done by the animation department. They spent a lot of time in the early stages of film preparation doing animation testing with different walk cycles for the Assblasters and underground travelling for the Graboids. “Despite the fact that there is no shot in the film where the Graboid is seen underground, it felt right for the whole animation team to explore different options of how the new corkscrew shape would work. That helped us create a lifelike appearance for the ground breaching and in-air movements of the creature. We extensively researched the way the Graboids moved in the original series, but because of the design changes and more vicious mentality, we couldn’t re-use most of what we found there,” says Danny, animation supervisor.

“One of the great animation challenges was the Assblaster, because it had so many parts to animate and everything had to be controllable by the incredible rig that was built for us. Six tongues, nine large and 30 small teeth, 36 claws, and scales on top of the general body movement controls. “At the end, I think we were able to breathe life into a fresh concept, and I really hope that the hardcore fans will embrace the new, more modern design,” adds Danny.

The Compositing process

Our compositing lead, Alex, came up with a new and, frankly, revolutionary system for the compositing stage. “By using 3-D masks in Nuke and tracking UV coordinates on the UV layer render pass, we were able to isolate a volume-object with a customizable shape which we could then use as a selection for working on a particular part of the creature/object. By utilizing this technique, we gained full flexibility to adjust the appearance of the Graboid in the middle of numerous dust explosions and ground bombs being shot in camera. It gave us much finer control over re-lighting different parts of the creatures, which made them blend into the plates perfectly. We learned just how valuable this was when the compositing team had to go back and start removing reflections of wiring and rigging equipment captured on the lenses of Burt’s signature mirrored glasses.

On set VFX Supervision

On set for this project we did much more than expected. We 3-D scanned sets, all of the vehicles and the main actors. Despite the dense shooting schedule, we used every opportunity to prepare and do ground explosions and various travelling underground shots with a special rig designed by the art department, which was used to simulate the wake left by the Graboid travelling underground. During the shooting we had the CG creatures already built and used every opportunity to show the animation tests or even finished shots from the previous day to the actors to help them visualize the scale and the nature of the creatures we were building, so as not to leave anything to their imagination. That lifted spirits and gave a great boost of enthusiasm to everyone on the set.