Turf Round 2
In the previous blog post, we gave you the background to our character designs in Turf plus a few technical details on how we modeled them in Cinema 4D. Now let’s dive further into C4D and discuss a few issues we had with animation. We tackled a few challenges with motion, fracture effects, HAIR, and rendering time and we will now give you a technical run through on all that wholesome, 3D good stuff.
Setting Up for the Game
After nailing down the character designs we sketched out a storyboard for the movie. The first scene opens up to a birds-eye view of the stadium, then a close up view of the field, low to the ground just a little above the grass. The grass comes to life, peeling away from the field to reveal our two main characters, Spike and Winger. They fly and pass the ball between each other eventually kicking it through a goalie, also a grass creature, to score a goal.
Storyboard sketches
In animating the characters in the 3D environment they needed to move with agility. Their motions had to be realistic while they maneuver the ball, flying in midair. The Align to Spline tag was ideal for animating in Cinema 4D, but in order to use it we had to first rig each creature with a bones structure. After our characters were rigged we could then write the motions with Align to Spline, which we did using XPresso. For those of you unfamiliar, XPresso is Cinema 4D’s Node-based system that charts expressions out to let you control your relationships between objects, materials, effect parameters, etc, as you see it mapped out in the XPresso interface. To change the relationships you can simply drag and drop around the diagram.
XPresso Editor (Click for large image)
The result of our test after the rigging and Align to Spline was a successful performance by Spike and Winger:
HAIR Control
To make the grass we used HAIR. If you didn’t know the dirty secret, HAIR is actually a notorious post effect. Because it does not have any polygonal geometry, it does not work with Depth of Field effect or alpha. Converting them into millions of polygons to manually create depth of field was not an option; by the time it finishes rendering, our hairs would be gray. We eventually went with a two-pass render to correct this problem. However, we did look into the post-effect plugin, enDOFin by BlackStar Solutions. EnDOFin should give all our HAIR objects depth of field and save us from having to make excessive polygonals or render for long hours. Maybe we will check it out to see if this plugin lives up to the challenge, but if any of you out there have tested enDOFin already, we want to hear about it. C’mon, don’t be shy now.
Quick-Thinking Particles
In the climax of the movie, the goalie makes its appearance as a hovering wave of turf. With a swift kick one character decimates it into bits of grass and dirt for the goal. To create the fracture effect from the “explosion”, the best way was to use the Thinking Particles plugin with XPresso. With Thinking Particles rather than applying forces or dynamics, we kept the fractured pieces together as a whole and let the plugin automate the explosion using the deflector we added on the ball. Thinking Particles calculated the dispersion of the particles, but we still used XPresso to control the flying bits during the explosion.
The effect worked smoothly, until we ran into a problem with the particles: after applying the dynamics to make particles bounce off the ground in Cinema 4D, some of them seem to hover and twitch in mid-air just before they land back down. To fix those annoying hovering bits, we wrote a code. It applied only to particles of low velocities, targeting the twitching pieces and had them freeze positions.
The second, more problematic issue that came up was with network rendering. Thinking Particles does not work with Cinema 4D’s NET Render because each machine calculates how to render the particles ever-so-slightly differently. When assembled together result is an awkward, choppy particle effect. Not desired. However, with our cunning Animal brains, we found a solution to NET Render the Thinking Particles, which we will reveal in another blog post. Look for the juicy step-by-step tutorial soon.
Never Sur-Render
MoGraph is a great module that could save a lot of time in workflow and rendering. The module clones objects and automates the effects and motions when applied. We needed to fill the soccer stadium with thousands of seats and since it was a perfect opportunity to use MoGraph, we used the module to duplicate all the seating. But when the scene was rendering, our machines kept running out of memory. At first we did not know what it could be, but as it turned out, the problem was MoGraph. The large number of stadium chairs was simply too many to keep in MoGraph. Therefore, we converted them into one object. This is one particular situation where the supposed time saving program actually betrayed us. But we forgive you, MoGraph. We cool.
However, the biggest render time-sucker of all is actually lighting. That is why we worked around Global Illumination (GI) effects as much as possible. GI effects can be useful tools. They consider all objects in a 3D environment and how light reflects between all surfaces. In most scenes throughout the movie, however, we did not use GI; rather we manually added the lighting and reflection. By combining multiple lighting tricks we were able to generate similar results but save on tedious rendering time.
So there you have it, the story of Turf from its conception to the production. We want to thank David Beckham, Moby Dick, and Zeus. Check back our website when we unveil the final movie. We know you can’t hardly wait.