3D, Animation, Compositing, Fluid Simulation, Particles

What’s lurking under the Liffey? Liquid Simulations


For this weeks blog we take a look at how we put a giant monster in the River Liffey.

We were asked by a client to create a giant Godzilla type of monster, but constructed with swarming smart phones and tablets.

We worked with the client on different concepts of what this phone monster would look like and so Phonezilla was born!

In creating the concept art, we looked at the various incarnations of Godzilla – old and new, as well as the great myriad of Behemoth and Daikaiju reference available online. Among our own office favourites, we researched and considered the scale and appearance of the beasts from films such as Pacific Rim, King Kong and even Ghostbusters (Mr. Stay Puft/Gozer).

Having decided to go with a more reptilian form, we got to work on refining the concepts further, working out the best way to meet the client’s requests; Phonezilla should have had a gigantic screen covering it’s belly, but having worked on the concept and exploring the envisaged practicalities of this in the modelling stage we found that for maximum impact it would be best to have the monster’s head be the screen.

Once the client agreed, we were back down to delivering the final concept and setting to work on the task of modelling the creature.

Phonezilla rough Concepts
Phonezilla rough Concepts

We were able to begin work on the modelling and animation based off the scripts and storyboard before the day of the shoot.

Our animators used CAT (Character Animation Toolkit) which is a strong toolkit inside of 3ds Max, we needed to use a custom rig on this project. We chose CAT for its flexibility, it allows for straightforward customisation of preset rigs (3d skeletons) and transference of data with no hassle. This meant we could modify an already existing IK rig, rather than building one from the ground up.

phonezilla_rig_01
Phonezilla Rig and Basic Mesh

Because the creature was so massive we decided ahead of time to animate at 75fps (frames per second), normally CG animation in Europe is 25fps, the additional frame-rate would allow us to control the speed of Phonezilla in post, slowing him down to reinforce his size.

We spent some time studying other Godzilla films, particularly the 2014 film, but also the Godzilla cartoon and other monster movies such as Pacific Rim. We wanted to get that sense of a massive object emerging from the Liffey, displacing huge volumes of water and dominating the landscape.

phonezilla_rig_gif
Phonezilla Movement Animation

Another part of emphasising the scale of Phonezilla was our use of the camera. We knew the shoot would be taking place just above sea level, and this gave us an idea of how to position the camera. Phonezilla’s whole body would never be in a single frame, he’s just too massive!

The camera chases after Phonezilla trying to keep up with him and showing just how hard it is to fit him into shot. We also added some strong [position and rotation] noise to the camera at the end of the shot. This gives the impression that Phonezilla’s roar is so powerful it causes the camera to shake violently.

One thing which was going to be vital was how we were going to realistically place Phonezilla into the environment. With all of the CG (Computer Generated) water which was going to be involved reflections and colours was going to be important.

We were present on the day of the shot to take some HDRI (To find out more about HDRI ( High Dynamic Range Imaging) see our previous blog post here) and other reference images to make sure we matched the environments correctly.

GLUE-Phonezilla-HDRI
Phonezilla HDRI Setup

When we got the footage from the shoot we realised we may be limited matching up some of Phonezilla’s full animation with parts of the shot. At this point we could have edited the animation to fit the timing and movements of the camera or we could re-create the environment.

This raised it’s own issues, Phonezilla was meant to be placed in the Liffey, near the Samuel Beckett bridge and in front of the CCD! How were we going to create so many iconic areas for people who see them everyday!

Thankfully we had an abundance of enormous reference images we took on the day of the shoot and we got to work stitching these together to create the landscape we needed.

Phonezilla reference images
Phonezilla Reference Images
Phonezilla Liffey Backdrop
Phonezilla Liffey Backdrop
Phonezilla environment setup
Phonezilla Environment Setup

Now we have our environment, colour, lighting information, shape and animation next we begin working with our liquid simulation.

We break it up into separate parts, the main box of liquid interaction and the remaining parts of the river.

Getting the physics correct for such a large creature can be a tricky process, the larger something is the slower it appears to move. We wanted to get the idea across this was a larger than life phenomenon so this was important to us.

The simulation works similar to a particle system with built-in physics, so we created the large body of water and animated the shape of Phonezilla to rise up through it.

This can be a heavy file for a computer to handle as it has to make a huge amount of calculations for each frame. For example our simulation had over 60 million cells [particle grid spaces] to calculate the correct movements of the fluid.

We added in some source objects around the spines of Phonezilla and slowly animated down the amount of water so this would create the effect of the liquid simulation continuing to stream down after he had fully stood up.  

To create the constantly moving mass of phones we used a particle system, similar to one used for the 5000 CG birds here. 

This time we created several different phone and tablet 3d models and plugged them into the particle system instead of using the bird model.

We then used the shape and volume of the animated rig and basic skinned mesh we created as a base for the phones to stick to. We made the main animated rig unrenderable so now we had just the particles visible. We set them to constantly swarm around the mesh so they aren’t static which will help give energy to Phonezilla.

Phonezilla-Particle-view
Phonezilla Particle View

View the finished video below:

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