is a treasure trove of tormenting and tormented sea creatures, elaborately designed and created by the artists at Industrial Light and Magic. Our ZBrush reporters recently talked with some of the artists at ILM to get the bigger picture of how ZBrush contributed to this computer generated feast.
Huge thanks and congratulations go to these artists, their crews, and the studio. Geoff Campbell, model supervisor at ILM, Sunny Li-Hsien Wei, artist, Jung-Seung Hong, artist and their crew were faced with a huge challenge: using geometry to create the massive quantities of sea life, sea-based costumes, tentacles, barnacles and other surface details would strike fear in even the most intrepid of visual effects artists. Knowing that they couldn't resolve their challenge with 2D texture painting artist Sunny Wei turned to ZBrush to see if it could solve some – if not all – of these challenges.
ZBrush became the primary solution after testing revealed that 32-bit real-world displacement assured the artists that they would get what they sought, regardless of where the map was created. In addition to the detail inherent in a 32-bit solution, ZBrush provides artists with the "ability to get what you see. ZBrush gives you all the detail control you need to create really well-thought out maps," says Jeung-Soon. "I don't see any alternative to ZBrush for that." The crew used ZBrush to create the countless sea lives that lived on all the digital creatures, including the surface detail displacements such as Davy Jones' wrinkles, his crew's extensive sea life adornments and the Kraken's hundreds of suction cups.
The process was complex: artists started by adorning each creature with countless low resolution sea life geometries, and their ZBrush displacement maps, and then adding surface details and displaced sea life details directly to the body mesh.
"We first built really simple geometries for all different kinds of sea life in Maya. Many of them, like barnacles, mussels, and seashells, were going to need really elaborate displacements. Once we had laid out the simple UVs for them, we brought the low resolution polygons into ZBrush to be subdivided and sculpted into very detailed ZTools. The sea life polygons attached to each creature's body mesh were kept very light to maintain fast interaction. Each of these little polygons became life-like sea life ornaments once we applied the ZTools displacement maps." says Jung Seung.
ZTools became a fundamental ingredient used in displacing each creature's base mesh. With each modeler creating ZTools, the sea life library of ZTools grew to include several types of barnacles, limpets, starfish, cone shells, snail shells, and even a dead fish. "We used ZBrush's projection master to place the ZTools on the creatures"; surfaces, which would give us displaced surface details with all kinds of sea life elements."
"ZBrush's fast interaction in3D space with a densely subdivided mesh was key to making this work."
Within Zeno (ILM's proprietary software package on which all the studio's tools are built), the crew had developed a face-set system which allowed artists to use a part of a mesh, with either individual UVs, or UV sets, each with its own texture map. Using a plug-in they wrote, artists were able to export OBJ files out of partitions, and import displacement maps into corresponding partitions, thus making "OBJ files ready for ZBrush sessions, just a simple click away. ZBrush's morph target system was used to get the exact amount of displacement we needed without distorting our original mesh."
In practice, Jung-Seung was able to break Davy Jones into multiple partitions, bring the desired section of mesh into ZBrush, and create a detailed displacement map for each portion: "Davy Jones' head alone ended up having 10 displacement maps made from ZBrush. "He adds that "ZBrush's fast interaction in 3D space with a densely subdivided mesh was key to making this work."
Sunny expands this thought, saying "Because there was so much sea life, I could never create individual geometry. ZBrush let us paint, and see our painting in real time, so we could make sure the art looked like the render. Once we exported the map, the TDs figured out how to make everything look the way they should!"
ZBrush came to the artists' rescue for more than just detailed sea life. Using ZBrush's standard brush, artists were able to create Davy's wrinkles and scars. His left leg, a coral-infused rocky surface, needed much more complexity than the simple sea life implants described above: Modeler Martin Murphy created numerous alpha maps out of all kinds of rocky terrain. Used in projection master, these alphas helped artists create all manner of surface details. Jeung-Soon adds that he frequently used the single layer brush in the projection master. "Mixed with variations of alpha maps, and little tweaks on ZIntensity, it became my favorite tool for creating surface complexity. I would also find myself using the morph brush: When I found that my sculpting went too far off-balance, this tool would help me go back to a clean surface on a partial area, which was great to insure well-balanced details."
As far as details were concerned, the much-feared Kraken took details to the extreme. Sunny Wei found ZBrush to be the perfect tool to handle the creature's multiple, varied suction cups and detailed tentacles. As he said, "polygons wouldn't give you the flexibility, so we had to use displacement maps, and with the geometry change, you can still see the detail." The artists created a library of suction cups in ZBrush. "Each suction cup was different, and there were up to 100 per tentacle, we would build them and apply them randomly on the tentacle. When it was time to render, the TD could choose what percentage of the cups were changed, and which displacement we wanted to apply to each cup. Because they were rendered procedurally, they all have a different look. With ZBrush, we were able to create 10-20 versions, apply each differently."
"We knew ZBrush would become a modeling tool that would free us up in a more fluid way without holding back our pipeline."
Both Sunny and Jung-Seung emphasized ZBrush's ability to help create intricate, unique creatures, saying they relied on the application's ability to show them what they imagined. Integrating ZBrush into the ILM pipeline became the "standard procedure for making difficult displacements. We knew ZBrush would become a modeling tool that would free us up in a more fluid way without holding back our pipeline. Now ZBrush is one of tools that we use for our pre-production as well, as it helps us visualize creature designs and concept arts in much more flexible and faster way."