Image-Based Lighting (IBL) is the CGI technique that involves capturing an omnidirectional representation of real-world lighting information as an image with a high dynamic range. This can then be used as a reference and starting point for recreating matching lighting for digital assets and characters in that same location or environment. Lighting computer-generated scenes with captured real-world light values can increase realism and help integrate digital imagery and real-world imagery. The process of image-based lighting starts with what is sometimes called capturing a light probe.
To help freelancers and crew who need to provide IBLs for Weta projects, VFX Supervisor Erik Winquist decided to make a definitive guide on how to capture IBLs. As Erik and Weta are keen to see standardization, they have agreed to release this internal video to help artists everywhere.
Weta Digital IBL Video:
Erik Winquist joined Weta Digital initially as a compositor on The Lord of the Rings: The Two Towers. He was visual effects supervisor on I, Robot and Peter Jackson’s remake of King Kong, where he supervised the jungle sequences, notably Kong’s frenetic battle with three savage ‘V-Rexes’. His credits as a VFX Supervisor extend to Avatar, Rise of the Planet of the Apes and Dawn of the Planet of the Apes. He has been very involved with integrating Weta Digital’s cutting-edge performance capture technology and IBL production workflow. This focuses on integrating digital performances into physical sets. Erik recently joined our fxpodcast discussion with Paul Debevec on Virtual Production (listen here).
In the late 1990’s, Paul Debevec developed the technique of High Dynamic Range Image-Based Lighting, where panoramic HDR images are acquired on location and then used to illuminate computer-generated objects, making them appear as if they were truly in the scene. Erik has extensively used this approach and Weta Digital shoots IBLs as standard. On a recent trip, Erik realized that it would be helpful to make a video to explain the ‘standard’ Weta Digital approach to help standardize the capture process and facilitate the general capture and processing of high-quality IBLs.
In a world environment where crews are often forced to work remotely and VFX teams cannot always get on set, it is vital to standardize the approach to IBL captures so as to allow for the most accurate on-set process possible. The video not only explains the core process and Weta tips and tricks, but it clearly discusses preferred gear and brands of photographic equipment. While this video was originally designed for internal use only, Weta has agreed to share it in the hopes of informing on-set teams based on their years of IBL experience.
Procedures and Gear
This video is the de facto standard at Weta for their major productions. The approach is used on all their projects as a matter of standard procedure. First amongst Erik’s supporters endorsing this video outside Weta Digital is Paul Debevec. As you can hear on our podcast, he joins others in agreeing that the Weta approach addresses all the key technical issues as well as providing a great guide to the best gear and production sensitive procedures that balance VFX crew needs with the demanding schedules of major productions.