basics: Dome lights

One of the best ways to light a scene realistically is to use a Dome light

Achieve efficient, realistic lighting with a Dome light

If you’re new to CGI, you may feel that there are far too many tools to choose from in a dizzying array of software. This series aims to break everything in CGI down to the very basics, so that every artist can be armed with the knowledge of which tool is best. We continue our look at lighting this issue by exploring Dome lights.

The use of Dome lights has been one of the greatest advancements in CGI creation over the past decade. Bathing a scene from every direction used to be computationally intensive, but with advances in both hardware and software, the Dome light has emerged as an efficient way to start lighting a scene.

This is because a Dome light can embed an image-based light image (IBL, also known as HDRIS). This is a single image of a real environment or one created by an artist which, when mapped into a Dome light, instantly re-creates the lighting environment.

These images are usually saved in a 32-bit format that captures nearly the full range of available light, and allows lighting to be created with a rolling falloff with no ugly clipping or banding. As the images have a full range of captured light they can be adjusted either with more power or less to help set the desired mood of the image.

While there are applications that can create IBLS, there are countless images available that re-create everything from a rocky vista to a photography studio.

Dome lights are also highly computationally efficient, which means it can be a good idea to use a spherical camera in an existing scene to create a HDRI map of the background. Placing that in a scene creates no loss of light fidelity, but enables the artist to concentrate on the primary geometry with little slowdown.

The biggest caveat with using Dome lights is that they solve so many problems that it can be easy to neglect other light types. This can be a mistake, as adding extra light to highlight key objects will always make a scene feel more alive than just using a Dome light.