3D Lighting Artists - Virtual Photographers

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Lighting a Scene in Film

light through trees ambiance — source: pxhere

Lighting a scene for film may seem straightforward, but it's an art on it's own. It's the art of the director of photography and lighting artists. Lighting a scene in 3D is surprisingly similar to this.

In the digital world, the concepts of traditional photography still apply, but with even more control. It uses the same skills, lighting theory and techniques to manipulate light, shadows and color to effectively convey the mood of a shot to the audience. And as always, it's main goal is to recreate the emotion of a scene, as established in the scenario, concepts and color script.

The artist has to produce interesting contrasts, create depth in the framing and lightly play with colors to to create a well exposed image. References for the lighting come from different sources: the lead lighing artist, the art director, the film director in the form of concepts and color scripts.

Lighting a Scene in 3D

What 3D brings to this art is an infinite control over the lighting conditions, natural and artificial, diegetic of not. Virtual lights can vary any of their parameters over time, making them unbound to their real-world physical construction or realism. A light can be infinitely big, hidden behind a solid object while still projecting light through, etc. It can also change color, size and focal point, animated like a character.

It also circumvents the limitations of real-world time, avoiding the hassle of changing light conditions, for example during the short, but coveted 'magic-hour'. 3D lighting allows for the ultimate control over photographic conditions and allows for cheats that would otherwise be impossible in real-world conditions.

However, the drawback is that it takes much more time to create everything than to snap it from nature. In 3D animation, not only are you having to set all the parameters for your virtual camera, but you are also constructing the content of your shot (the subject of environment). Furthermore, trying to recreate perfectly realistic 3D scenes is even more demanding and time-consuming in order not to fall into the uncanny valley.

Tasks of the Lighting Artist

light source artist hand — source: pixabay

Building the Final Scene

The lighting department on a CG production takes 3D scenes from shots assembled by the final-layout, after everything has been finalized in texture and animation. Then, they add virtual light sources, like a sun, an ambiance, volumetric effects and other light sources. Similar to a lighting artist on a film set, the 3D lighting artist is responsible for the final look of the shot they are working on.

Creating the Lighting in 3D

The main job of a 3D artist in lighting is to set up the lighting conditions for every shot in a scene. Artists usually work on all the similar shots of a scene, to ensure continuity in the lighting between different shots. For example, an artist could do all the counter-shots in the same angle of a scene, and the other will do the reverse angle. Artists are usually supervised by a 'lead lighting artist', that will establish the overall look of the scene and distribute the shots to his team of artists.

Creating masks for compositing

sunset horses mask shadow lighting — source: pixabay

The lead lighter will also generally think about creating the material required for the compositing of the scene, after lighting. Sometimes, the lighters are also the compositers, otherwise the lighting department must collaborate with the compositing team to ensure proper rendering of the different render passes.

Debugging technical problems for render

Rendering time, is also the time where all the technical problems appear, for a lot of 3D animated productions. Therefore, the lighting artist must have an incredible attention to details in order to spot and flag problems to the appropriate department. Problems can range widely depending on the methodology of work of the studio and the ability for technical directors (TD) to think and prevent problems beforehand.

Here are a few of the problems that can happen in production:

Missing textures
Wrong UVs on objects
Scene crash when building the scene from final-layout
Render crashes

Rendering images

The final step of lighting is to render all the frames for each shot. This is usually done by sending the 3D scene to a render-farm that will distribute each frame to different computers. The render-farm is an array of computers linked together by a fast network. It is managed by a software that distributes the data to idle computers, to maximize efficiency. The render farm is closely watched by the IT department, for heat dissipation and power management. Additionnally, a render wrangler supervises the errors returned by the render-farm and resubmit failed tasks, when possible.

The step of rendering is extremely time-consuming (for the computers), and is handled by either the CPU or GPU, depending on the render engine used for the production. Rendering also uses a lot of RAM.

The exact purpose of this step is to convert the 'preview' seen in the working view of the 3D software into a final image for film & TV. The renderer calculate how light sources are bounced onto materials and back into the camera, to produce an image. This is exactly what a camera does, except it is done instantly in the real-world. The more realistic and complex your scene is (in terms of lights, or 3D objects), the longer it is to render. Also, it is important to note that doubling the resolution of the final image will quadruple the render time. As both the vertical and horizontal resolutions are doubled, the actual area to render is actually quadrupled.

Career Paths

The lead or senior lighting artist coordinates with the art director and the director, to research and determine the final look of each scene or group of shots. Each of those 3 roles coordinate together to act as the director of photography would in live cinema. However, there is a tendency on big-budget animated productions to still have a director of photography coordinating the look from the lighting and compositing departments.

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