Issue link: http://digital.copcomm.com/i/832212
82 CINEMONTAGE / Q2 2017 82 CINEMONTAGE / Q2 2017 Aside from these price point comparisons, however, there are even more important limitations to GPU rendering. While independent artists working on small to mid-range projects will benefit from GPU rendering, others — namely those who work on large-scale projects — will want to continue rendering on CPUs. As Fajardo says, the reason CPU renderers are the right choice for big visual effects and animation companies today is because CPUs have access to much more memory than GPUs. This is important in massive visual effects scenes, like those in Gravity (2013), where the volume of 3D data is very large with very intricate models, high-resolution textures, volumetric simulations and displacement maps. Due to the much smaller memory capacities of GPUs, these kinds of scenes require rendering with CPUs that have access to copious amounts of RAM. Thus, it is Intel CPUs that power rendering for Hollywood, and this will remain so for the foreseeable future. The exciting development for studios doing massive productions is not so much GPU rendering but the advent of cloud rendering. Sending large scenes to render on cloud services containing vast numbers of CPUs greatly increases the power of small to medium facilities, allowing them to compete with bigger studios without spending a fortune on building and maintaining on-site infrastructure, machine rooms and render farms. However, GPU rendering is an exciting new technology that will continue to become more important, and Solid Angle is hard at work at GPU support in Arnold (Word on the street is that Solid Angle decided to concentrate on new features and improvements in Arnold 5 before making a GPU version). SO, WHAT'S NEW, ARNOLD? Let's discuss the new features in Arnold 5. To start, the internal API (application program interface) has been reworked, extended and simplified, making it much easier for those who want to write Arnold- powered applications. Arnold 5 is also faster. Many functions have been optimized, resulting in significant speed increases in ray tracing and rendering. Large OpenVDB volume caches (used to create volumetric effects for such things as clouds, smoke and explosions) are twice as fast as are indoor scenes with multiple GI bounces (indirect lighting) and objects with high transmission depth, like realistic-looking glass. Opacity-mapped surfaces, such as tree leaves, render up to 20 percent faster, and there are many other examples of smoother and faster rendering. A ray tracer like Arnold works by tracing the path of many rays from a 3D camera through the entire scene. If the sample rate is not high enough, noise and grain can appear. Removing it is done by increasing the sample rate (which also has the result of increasing the render time). Arnold 5 includes several sampling optimizations. There's a new technique for dithered sampling, which improves the visual distribution of noise at lower sample rates and improves sampling results with soft shadows, making your renders look smoother with less noise. Lighting has also been improved. A new approach has been taken for direct illumination sampling for TECH TIPS CONTINUED ON PAGE 88 Above: Arnold 5 has a remarkable skin and hair shader, as seen here in this rendered image from the 2017 film Logan. Image by Image Engine Top, right: Decreasing melanin content in Arnold 5's new standard hair shader. Model courtesy of Zeno Pelgrims Bottom, right: From 2015's Star Wars: The Force Awakens. Image from Hybride