PIPELINE TECHNIQUES: Discover real-time lighting techiques
Learn to light a cinematic with Joey Lenz and Phil Liu
in this tutorial, we’ll cover the basics of how to use an industry-leading game engine, like unreal 4, for a cinematic render. We’ll go over per-shot lighting techniques in a real-time environment, material setups for painterly falloffs and gradients, and custom render passes for compositing and layering of effects. For this black-andwhite study, we were inspired by Blizzard’s Diablo character, and the under-lit mood was derived from the original Frankenstein movie for a horror theme. The bust was sculpted by Phil Liu in Zbrush and was later optimised for unreal 4 importation. We used a PBR workflow as a base but it evolved with more artistic choices to get the exact look and feel we were after.
Lighting choices in the world of cgi, it’s a common practice to use global illumination technology to assist with rendering very realistic indirect lighting. however, it’s not always necessary for every case depending on the intent or how much control is needed over the lighting. in our case, we were going for a very specific look, and we felt it would be better for us to manually determine every aspect of the lighting. Therefore, each light in our ue4 project was set to Moveable and no precomputed, diffuse indirect lighting was used. 02 Per-shot lighting Games use a lot of in-theround lighting, where it has to look good regardless of where the player/camera is looking. Our project required the camera to be in a locked position. With our render only having to look good from only one angle, we could use per-shot lighting techniques and get away with more. since we didn’t have to worry about lighting optimisations traditionally found in games, like overlapping dynamic light count limits, we had the freedom to use as many lights as necessary. For instance, some of our lights were used to just add small accented, local highlights.
03 Falloff effects sometimes you want specific areas to have soft, shaded gradients. While this can be achieved with lights, it may not always work for every circumstance. Dark lights can re-create this look, which is when a light’s intensity has a negative value.
essentially, it sucks up pre-existing light, leaving that area darker. ue4 does not allow for this, so we had to use a different method.
We ended up using planes with procedurally-generated gradient materials and placed them between the bust and the camera for control over the falloffs. A similar technique was used for the flickering glow effects.
04 Render passes custom render passes were created for more control in the compositing stage. This was accomplished with the use of materials tailored for specific passes. For example, RGB mask/mattes used materials with their shading model set to unlit so they would give us flat base colour values without lighting/shading information on the geometry. Another pass included isolating the flickering fire lights emitting from the head and to create a matte out of them. To do this, a white material was assigned to the geometry, and only the fire lights were visible in this pass.
High-res screenshots We needed highresolution renders and ue4 offers a tool for this. in the viewport, there is a drop-down arrow in the top, left-hand corner. When you click on it, you’ll see the high Resolution screenshot tool. A new window then appears with an option called screenshot size Multiplier. We set ours to 4 which gave us renders 4x our screen resolution. The idea behind this is so you can work with higher-resolution renders that will eventually be downsized for the final output. The results tend to be sharper than if you worked at the final resolution the entire time.
Compositing There are many programs and ways to composite these days. We kept it simple and just used Photoshop. All the render passes were imported as layers and stacked accordingly. For animated layers, as well as keyframes, we used the Timeline tool, which can be found under Photoshop’s Window menu set. With this, we were able to scrub through the animation and edit layers until we had results we were happy with. Adding FX was one of the final touches for the project. We rendered them out from a program called Werble and then composited them into our Photoshop scene.
Joey Lenz and Phil Liu polyplant.co the-last-pixel.com Bio Joey is a lighting artist in the videogames industry. He’s worked on games like Halo 5, Modern Warfare Remastered, and the Forza series.Phil is an environment artist for Monolith Productions. He has worked on games like Middle-earth: Shadow or War, Guild Wars 2: Heart of Thorns and Halo 5.