MPC Film’s Head of Optimisation Will Earl, 3D Modeler Gagandeep Singh, Lead Software Engineer Curtis Andrus, and then Rendering Engineer Joshua Senouf, outline some of the work that went into rendering the forest environments found on the back of a mountain-sized Pokémon called Torterra in Detective Pikachu.
MPC Film is no stranger to large action sequences involving the destruction of CG environments. However, for Detective Pikachu, they wanted to improve upon many of the challenges they experienced on previous shows. One is being able to build and render larger environments, and still maintain the visually complex movement from animation and dynamics. With that in mind, the team have modified the way they load and render geometry to make it more efficient and developing new workflows for simulating trees and extending the pipeline to handle them.
This sequence required the creation of a cohesive environment that could be creatively animated, physically simulated and efficiently rendered, in addition to around 358,000 trees, 355,000 rocks and 7,350,000 million grass patches. Each tree model takes up a million polygons, including a face per leaf, with rocks taking 20,000 faces and grass using 480,000 faces.
Populating the environment was now done by environment artists working within SideFX Houdini, allowing artists to easily generate millions of scattered trees. To efficiently render them, the MPC team implemented Pixar’s InstanceArray feature into their rendering toolset within RenderManForKatana as an alternative to Giggle Instancing. Better memory-mapping of data within InstanceArrays significantly reduced the time taken to generate instance information at render-time and sped up the path-tracing process.
Statistics from the render comprised of 3.5 million instances using RenderMan
Animating and destroying terrain is a relatively trivial task to achieve at MPC Film through the animation and FX pipelines, but more difficult to achieve in the environment pipeline. Hero simulation of trees was done using MPC’s FEM-based Kali toolset, which produced more stable results than rigid-body dynamics.
Given the number of trees required, they weren’t prepared to stress test our FEM simulations on more than 1,000 trees. Hero trees, which were required to bend and break, were simulated using both Kali and Houdini – FX artists could load up the instanced trees in order to calculate collisions and perform rigid-body simulations on or additionally convert some of the instanced trees to fully simulated trees. – thefocus.com
To learn more, read the full article here.