How to Do Cinematic Lighting in Source Filmmaker

Source Filmmaker, created by Valve, is a great tool for creating animations using the Source engine. Its easy-to-use interface makes it an ideal starting point for new animators. However, many newcomers are so focused on perfecting model animations that they overlook the potential of effective lighting, often resulting in animations that feel incomplete. In this tutorial, you'll discover how to master lighting techniques in Source Filmmaker to elevate your projects to a cinematic level.

To use SourceFilmmaker, you will need:

1. A Steam account
2. SourceFilmmaker Installed

Once you've finished animating your scene, it's time to do the lighting. (Note: This tutorial focuses solely on lighting techniques, not animation.) Although there are many parameters affecting light in Source Filmmaker, the most essential one is color, which you adjust using sliders similar to those on an RGB scale when selecting the light.

To simplify positioning, drag your light onto the work camera. This lets you move the light as if it were a camera, allowing for a clearer view of how it illuminates your scene. Most cinematic scenes in animation use three light sources that light up your subject: a key light, a fill light, and a rim light. These are represented by red, blue, and green hues on the character, known as 3-point lighting.

The key light is the most important part of your lighting setup, serving as the most impactful source of illumination in your scene. It divides your subject into regions of light and shadow, creating an interplay that adds depth and mood to the scene. Adjusting the position of the key light can alter the tone: for a more serious or dramatic theme, position it so that a larger portion of the subject is enveloped in shadow; for a brighter atmosphere, allow more light to fall on the character. Typically, placing the camera on the shadowed side enhances the cinematic feel, adding a deeper meaning to the shot.

The fill light is designed to brighten the shadows on the subject created by your key light. Placed on the shadow side of your subject, it illuminates areas that would otherwise be underexposed, changing the balance between the light and shadow sides of the subject. Typically, the fill light uses the same color as the key light but at a lower intensity, ensuring that the effect of the shadows isn't entirely lost. In Source Filmmaker, an easy way to add a fill light is to duplicate your key light, lower its brightness, and reposition it to the opposite side of your subject. However, keep in mind that while this method suits a digital environment, in real filmmaking, the fill light is generally set up in front of your subject on the shadow side to create a more natural and balanced look.

Rim lights create a halo effect around your character, sharpening edges and providing a sense of depth and separation from the background. Typically, these lights are placed on the same side as the camera to ensure that the effect frames your subject naturally. But when not using Source Filmmaker, they should be placed behind the subject.

Achieving this effect with Source Filmmaker requires a few precise adjustments to the original light. After positioning your rim light, find the shadowDepthBias parameter. Right-click on it and select the option to remap it to a slider—this action will open a new window where you can directly input values. Set the minimum value to -0.01 and confirm. Next, adjust the sliders by moving shadowDepthBias all the way to the left and shifting constantAttenuation to the right. Finally, tune the halo effect using the shadowFilter size slider until you achieve your desired look. Keep in mind that the lights are not meant to be red, blue, and green, as shown in this tutorial, but whatever color you want.

Beyond the lights themselves, there are specific camera settings that can affect the lighting of your scene. The first one is toneMapScale, which effectively controls the brightness of your scene. Next is bloomScale, which is what controls glare on objects in the scene. For the most part, this slider should always be set to 0, as it covers up detail on the subject. SSAOBias adjusts the bias for SSAO calculations, helping to mitigate unwanted artifacts like excessive darkening in shadowed areas. SSAOStrength controls the intensity of the SSAO, determining how emphasized the ambient occlusion appears in the scene. You can choose any combination of these settings depending on your scene, but the ones depicted above are generally the most useful.

Now that you have your lighting done, it is important to render your final work properly. Most people will either take a screenshot or export it as an image/video through the default settings. While this is easy, it will destroy your work's quality, making lighting effects such as the rim light barely noticeable. To get the best possible render, start by going to the timestamp of the frame you want and then right-clicking on your primary viewport (the window that shows the camera view). Select render settings, and fill out the boxes to match the image above. Then, go to export, and pick the file destination. Make sure you select PNG as the file type, and then hit export.