RSP Integrates the Arnold Render Engine for Production

“We were having continual problems with render capacity,” said RSP president and head of productionJohn Carey. “Our load kept going up. Over time, the demands of our work – meeting client and audience expectations – have intensified in terms of more shots with bigger, better and more realistic effects, which puts more pressure on all of our technical resources, but especially on rendering capacity.  As a matter of routine, we now produce work that a few years ago would have seemed impossible.

Mid-production

“In the period before we started testing, we were spending a lot of time and money optimizing renderers and buying more machines. But we didn’t want to just throw money at the problem. We wanted to fix it. While it would have been ideal to have moved to Arnold between shows, there really is no ‘between shows’ here so, regardless, we brought Arnold and some other rendering software in for an evaluation,” said John.

The decision to change rendering engines during production wasn’t taken lightly. The disruption it causes, the loss of look development and lighting work and the effort involved in integration can all create a sometimes unfair obstacle to adoption. “Put simply, once integrated the proposed render engine has to produce a level of efficiency that exceeds the combined cost of integration, plus the cost of work that needs to be redone,” John said.

“When faced with those criteria, in our view only Arnold was up to the task. It wasn’t painless to make the switch mid-production, but with Arnold it was successful. With the other options we tested, it would not have been practical.”

RSP’s work on the upcoming film project mainly involved photorealistic work that required accurate light transport precisely integrated with live action plates, plus specific work from the director that placed more creative demands on the team. What they were especially looking for in the renderers they tested wereperformanceandflexibility, a set of detailed, realisticshaders, and ease ofintegrationinto their pipeline.

In Control

“When using Arnold we had more control over the render, which simplified the integration and composite considerably. Straightaway, without fine-tuning, our first lighting pass looked better,” said John. “Nevertheless, we aren't searching for out-of-the-box looks and don't want to be limited by presets or even preconceived ideas of how something should look. At render time, we want to be able to do whatever we, and our clients, can imagine.

“Because a lot of factors affect on the look of our work, as pressure to deliver mounts, problems are often pushed downstream and all land in compositing. With Arnold, since the renders are looking better from the look development stage through lighting and on to compositing, even when problems are pushed downstream, the compositors are still starting in a better position.

“One of the main contributing factors, in my opinion, is the accurate approximation of thetransport of light. In most of our work, our clients capture plates, which means the actual transport of light is recorded. If what we render cannot approximate that accurately, our compositors will have a lot more work just to get assets to integrate and won't be able to spend nearly as much time making them look great.

“AllPhysically Based Rendering, or PBR, techniques purport to do that, but integrating synthetic images with real photography is the real acid test. Arnold integrates better simply because it approximates the physical transport of light more accurately.

Sampling and Subdivision

Darin Grant, vice president of engineering at Solid Angle, described the control Arnold affords to artists over their renders. “We generally choose to make working with Arnold as simple as possible so that artists get to focus on the image itself instead of the technical aspects of producing imagery,” he said. “However,samplingandsubdivisionlevel are two important parameters in Arnold that can significantly affect a render’s quality and complexity.

“We also give access todeep image compositing, andAOV, arbitrary output variable generation, has many options that allow tweaking in the composite, if that is the team’s usual workflow. Overall, however, Arnold has fewer parameters than is typical and produces reasonable images with very little adjustment of those parameters.

“Anyone can add features to a renderer but our goal is to add functions while not having to expose them to the user.  Furthermore, artists using Arnold are very skilled at developing workflows. Consequently, we share the source code to our integrations – which cover Maya, Soft Image, Cinema 4D and KATANA - with customers so that they can modify it and contribute improvements back to other artists in the community. “

Houdini Through HtoA

Because RSP relies heavily onHoudinisoftware fromSide Effectsas an essential part of their production pipeline, the team worked with Solid Angle to further develop the company’s Arnold forHoudini plug-in, HtoA. “The development team worked with us particularly to solve integration problems. We’d put tickets in and they turned them around as if they were in-house developers or a production partner, instead of a vendor.”

John feels they may have placed an extraordinary burden on all of the renders they tested, in that they had to support Houdini, if not directly, at least effectively. “Fairly quickly, we found that at that stage, Arnold had limited support for Houdini through HtoA,” he said. “But we also found that the team at Solid Angle was prepared to partner with us to make the integration work as smoothly as possible. Due to the short integration cycle and the scope of work in our evaluation, I wouldn't say that it was easy, but by working together with Solid Angle it was possible. The results speak for themselves.”

About Performance

Now, as the primary production renderer, Arnold is being used on three features and one TV show at RSP. Like John, Darin said that, unlike some other renderers, Arnold doesn’t have a distinctive ‘look’. However, the way that it renders complex production scenes with very heavy geometric and textural complexity is an ability they have cultivated - that includes fur, volumes and scenes with trillions of visible polygons.

He said, “Within the core of Arnold we have just released significant improvements in the rendering of interior scenes as well as a new subsurface scattering profile that retains even more high-resolution details in models than before.

“But, as much as any tool or paramenter or integration, Solid Angle focuses on performance - every new release has some performance gains. When performance improves, it allows you to render scenes that you may not have been able to before due to various resource constraints. So by focusing on performance, we also improve the quality of imagery our clients are able to produce within those constraints.www.solidangle.com