How do you use CG lighting?
Making an animated film brings all the elements of the real world into the screen. That’s why working with 3D images requires mimicking the attributes from the real world. For instance, if the scene features the outdoors, everything from the plant foliage to the grass has to look as detailed as possible, which is painstaking work!
Accuracy and convincing CG lighting are the key to making stunning, realistic 3D images. That said, illumination in CG has its challenges and sometimes we’re forced to apply creative ways of mimicking the real world or making the lighting of the film even better than the real world.
If say, you are working with an animated film and you are out of ideas when it comes to enhancing the CG lighting, here are tips to creating professionally lit scenes using any 3D program:
The Basics of 3-Point Lighting
To light CG films like a pro, you have to apply some of the most important illumination principles in the scene. The most common illumination technique used for portrait and cinematic lighting is the 3-point lighting technique. This technique can be applied in making stunning CG images as well.
As the name implies, this illumination principle is based on the placement of 3 different sources of light: the key light, fill light, and rim light.
Key Light: This is the primary source of light. The key light should be set 45 degrees in front and above the subject of the scene.
Fill Light: This light source adds soft illumination to the scene to banish shadowy areas in the composition and lighten the scene. The fill light is often set opposite the key light.
Rim Light: The rim light is a stark source of light. It is often placed behind the subject to add distinction between the subject and the background. The rim light creates a thin frame of light along the subject’s figure.
Observe Real Life Lighting
Observing how real-world illumination changes as the day progresses will also help you create photo-realistic images using any 3D program. Throughout the day, shadows and light shift and you have to mimic these changes to add realism to CG scenes.
Most scenes feature a mix of indoor and outdoor lighting. Nighttime lighting and daytime lighting are different so it pays to observe how the light changes in the environment to determine what type of lighting you want to achieve. Having a valid color script is also critical in making animated characters pop on screen.
Play with Different Light Attributes
Most 3D programs come with a host of useful light controls that allow you to create convincing lighting. Of course, you have to explore these controls and learn how to apply them properly to create photo-realistic scenes.
Premium 3D packages may be expensive but they do come with a variety of light-style controls that you can experiment with to see which ones could work in a specific scene. Some of these light styles mimic real-world lights. To create stunning, photo-realistic scenes, you have to know the basics! Here are some of the most basic light styles to keep in mind:
Point: The light source is from a single point, generating light in all directions.
Spot: The light is concentrated in one direction and the illumination has a narrow spread.
Parallel or Directional: This light-style mimics the sun, the light has no spread because the rays are parallel. The light spreads across the entire scene evenly unless modified to focus on certain areas.
Environmental: Also known as diffused light, this light style creates a soft, non-directional light that adds more shadow areas to a scene as opposed to illuminating and highlighting the scene.
Area: The light is emitted from a wide area. Usually, the light is represented as a fluorescent bulb or as the sunlight that comes from the window.
Volume: This light style mimics how light naturally behaves in a space, like beams of sunlight.
These light styles can be used in multiples or combined to create photo-realistic scenes. Using your 3D program, you can create cool light effects such as light that’s diffused for illumination, bright light like daylight for outdoor scenes, or ambient light for indoor scenes.
The atmospheric effects of light add a sense of depth in images. As we’ve highlighted in our guide on aerial perspective, this technique is used to define the appearance of distance between objects using color and tone gradations.
This technique can be applied to create detailed, hyper-realistic scenes. Most beginners tend to forget that light intensity changes throughout the entirety of a scene. They tend to apply consistent illumination, which isn’t very true to life at all. As the camera moves, the objects should fade or recede into the background and the color and light intensity will also fade gradually.
You have to create the illusion of depth and distance through clever light application to enhance the visual impact of the scene as well as suggest the distance of certain objects. Generally, the objects in the foreground should have the darkest values in the scene while the mid-ground objects are illuminated accordingly. The objects in the background should be de-saturated, gradually becoming less distinct as the camera moves further away.
Creating Implied Lighting
Adding shadows from an unseen object gives the impression that there is a world beyond the edges of the frame in a scene. This can be achieved by applying implied lighting.
Implied lighting adds interesting shapes to an image while also pulling audiences into the world you have created. This light technique adds a sense of mystery or wonder to a scene, especially when the light is obstructed from the audience’s view.
Learn All About Color, Temperature and Image-Based Lighting
To create an accurate, real-life rendition of CG lighting, you have to be aware of the color, the color temperature, and the right light specs that a scene requires. For instance, outdoor lighting can be a mix of bright yellow light from the sun and a blue cast from the sky. On a cloudy day, the bright light is replaced with grayish, de-saturated light.
Indoor lighting is much warmer than outdoor lighting but the color temperature will vary depending on the bulb being used for illumination. For residential use, bulbs that emit warm light is the most common.
Another technique that mimics real-world lighting in some scenes involves the application of warm hues in objects that are illuminated in the scene and the shadow areas are rendered with a blue cast.
Some 3D software also comes with an option for image-based lighting. This technique lets you manipulate light in a High Dynamic Range Image or HDRI that has the environment of the scene your 3D models are to be immersed in. Image-based lighting results in convincing, realistic lighting but it have to be augmented to achieve the perfect lighting effects.
Rendering a shot several times adds a sense of realism in a scene. Rendering a scene in multiple passes can be done in several ways but the most common involves rendering each light or a small group of lights as individual passes. Once the rendering is done, the scene is run through Photoshop or similar software so you can adjust the lighting until you have achieved the desired effect.
Collect and Study Image References
Some creatives think that collecting references is cheating but if you really want to make the lighting as hyper-realistic as possible, it’s worth trying out! You can search online for photographs that depict similar scenes that you’d like to create or grab frames from movies you’ve been streaming and study the references you collected to improve your own work. Check the photos/movie pictures and study the brightest parts of the scene, the dark areas of the scene, etc. Observe the color saturation in dark and bright areas and take note of any changes in tone or saturation as the camera moves further away from the scene.
Because you are not copying someone else’s work, collecting and studying these materials won’t violate the copyright law. Apart from improving your own work, collecting image references is also a great way to communicate ideas to your clients clearly. You can show the references you collected to a client to brainstorm, explore different ideas, discuss different light effects, or determine what the client likes or don’t like to improve the final result.
The Spill Light Effect
You can make your rendering look even more realistic by applying the spill light effect. The spill light is often missing in 3D renderings, which is a shame because its overall effect makes the scene look as natural as possible. This light style is the soft illumination that comes roughly from the same direction as your key light, covering a broader area than the key light itself.
For instance, if you are adding a sunbeam to an indoor scene, applying the spill light effect will soften the sunbeam so it doesn’t look unnaturally stark. You can also give a spill a richly saturated color to create a variety of natural-looking illumination, such as adding red and orange to the yellow sun to depict the sunset.
Improve Your Models
Optimizing your models help create believable looking scenes. Start by softening the edges of corners because corners are not perfectly sharp in real life. For example, the edge of a desk should be rounded or beveled in some way to make the light effect believable.
It also helps to build thicker geometry in your architecture rather than using thin surfaces all the time. Real houses have thick walls in movies, something that you should mimic in 3D renderings. This way, the walls looks like a cube rather than a plane, which minimizes light leaks in some scenes.
We also recommend pruning models that a shot could do without but go easy on the models or surfaces that cast shadows, global illumination, or reflections.
Over to you!
There you have it! Now you know how to use CG lighting like a pro.
Next, we’d love to hear from you:
What’s your #1 question when it comes to CG lighting?
Let us know in the comments below!