“The Sea Monster Shot was attempted for the trailer using RealFlow’s water-surface technology: RealWave. For the final version we decided to use RealFlows Hybrido system so we could have a highly interactive base water simulation.
“A team of 3 was put together to achieve the shot. Myself, (fluids simulation specialist), Grant Hewlett (Renderman lighter/render specialist) and Alex Parkin (a modeler and junior lighting TD).
“The shot was packed full of challenges:
The Scale: A 200 foot sea monster makes one hell of a splash, adding enough small detail within the large scale simulation meant simulating a vast, high resolution water surface.
The Length: 947 frames, approx 40 seconds - with the run up? Over 1,000 frames. That meant that, as we drew closer to final resolution, it took more than 4 days to see a new version of the base water simulation.
Time: We had 3 months from the kick-off meeting of the shot to simulate, render, and composite this behemoth of a shot.
Those were the known challenges going in. As the film VFX as a whole got closer to completion, we had additional issues like server space and overall bandwidth on the network. So we started a system of dailies early in the day, followed by overwriting the previous days simulation data until that would no longer work. To be honest there were many times during the production of this shot that I questioned if what we were attempting was even possible!”
“Hybrido was definitely the way to go for a shot like this. It allowed me to slowly build up the resolution of the base water sim while working out issues, like the speed of the character animation and exactly what needed to be visible to the camera by clipping everything outside of its frustrum. As we approached the final simulation over 30 million particles were being simmed all interacting with the characters.”
“The ability to split the various passes onto RealFlow Nodes made this impossible shot possible. In the final version there are 3 different exit splash simulations comped together, each simulation was broken into 9 square quadrants of the exit area of the seamonster. This allowed me to make each quadrant as dense as possible and really spread out the processing demand of the shot as thin as I wanted.”
In the end the full exit splash contained approx 50 million particles. By handing over such a dense particle sim to the lighting TD he was able to get away without using multipointing or any other "cheats" to bulk up the splash.”
The RealFlow RenderKit
“We used RealFlow RenderKit for Renderman and it was a great help controlling the huge amount of data both in the viewport and at render time.
The foam was a beast of another color altogether. After being able to separate the foam creation passes, rendering it became a monster. So we settled on a cool little workflow of rendering the foam particles out of maya from a top camera and using that render as both a color and displacement map on the final water surface. It helped greatly with render times and the added displacement gave the foam almost a volume at times that was cool.”
I've been using RealFlow for over 8 years - since version 3. I've watched the program grow with each new version and I'm amazed at where it is now. After doing this shot using RealFlow, there is no shot I would ever say is impossible!”
Effects in general usually live somewhere on the edge of most pipelines, because of the need for stand-in geo and baked anim. RealFlow is no different, but moving sometimes large data sets around was a breeze.
I will definitely reach for RealFlow the next time I'm faced with a shot like this.
10 x 16 Core Linux boxes.
And to finish…
I'd just like to thank Andy Morley the Vfx sup on Pirates for giving me the shot, Grant for making it look great in Renderman with the RealFlow RenderKit, and Alex for putting up with my sometimes crazy demands and attitudes.