After I posted my Danny’s Dream short a few weeks ago, a few people wrote to ask about the V-Ray settings I’d used to render the sequences in about 5 minutes per frame. Instead of answering individually, I thought I’d post and discuss my settings here.
A few general comments to start with: First of all, rendering a three-minute HD short on a single workstation, however powerful, is not how such things should be done. Anyone with any sense will do this on a render farm, at least a small one. But if, like me, you insist on doing things by hand, you’ll have to make compromises. Painful ones. Lighter geometry, smaller, filtered textures, post-pro DOF and clamped renders will help speed up your render at the expense of quality. Where I really hate compromising though, is on materials and noise. Noise may be artistic in stills, but it’s just distracting in animations, especially the static kind of noise V-Ray produces. The settings below take this into account. One thing you won’t see here is my material and light settings. Basically, I use high reflection subdivs on my materials (anywhere between 32 and 96 for glossy materials) and high V-Ray-light subdivs (between 64 and 120).
The settings below are those I used for the hallway sequence pictured above. They may not work in all situations. First of all, most of the illumination here is direct (invisible V-Ray Plane Lights just below the fluorescent tubes), with GI playing only a secondary role. This means the GI doesn’t have to be very precise. Also, while the scene is reasonably complex, there aren’t that many nooks and crannies. Classic interiors with complex cornice moldings, for instance, won’t work well with such settings and will require much higher-quality GI. Note that I pre-calculated the GI here, because there are no moving objects. Sequences with animated geometry, such as the elevator scene, use the same settings but with a higher-quality GI using the animation preset. In all cases, I render my scenes slightly underexposed to limit the amount of rays in the scene. You can always tweak the exposure in post (within reason).
The values in red are the ones to watch. Scroll down for some explanations:
MAX RAY INTENSITY: Avoids fireflies and noise when there are bright lights and reflections in the scene.
TWO-PIXEL AREA FILTER: Gives a soft, more filmic, edge to the image.
LOW AA MAX SUBDIVS: 6 is probably the lowest you can go. All the work is done by the DMC sampler.
COLOR and DMC THRESHOLDS: If you want fast, don’t use the DMC sampler threshold here and raise your color threshold until you see noise appear. 0.02 worked well here but you may have to go lower in some situations. My DMC noise threshold is set a bit lower at 0.01, but both are actually quite high compared to my stills settings.
LWF AND CLAMPING: I hate to clamp as it drastically limits what you can do in post, but in this situation, it was a must as it gave a nice speed boost and a cleaner image, albeit one devoid of any dynamic range. This means I had to render a separate pass with just the fluorescent lights, which I used for glow and flares.
GI & LC: The IM is set at low quality, but the Subdivs and Interpolation samples are set at 50 and 50 to eliminate all blotches in the corners. Such a smooth IM is nice and clean for scenes that rely a lot on direct lighting but wouldn’t work as well in scenes were the GI does more of the heavy illumination lifting. The LC is left pretty much at default but I use it for glossy rays for a small speed boost on reflections. Retrace is on, which actually increases render times slightly but it’s a must to avoid light leaks.
MISC SETTINGS: I use a small bucket size because I’m just impatient, and don’t forget to tick Embree if you use Intel processors.
That’s pretty much it. Ask if anything’s not clear and let me know what you make of these.