Published: April 7, 2025 | Last Updated: April 11, 2025
SHADING TECHNIQUES DEFINITION & MEANING
Shading in computer graphics is the process of simulating light, shadow, and surface details on 3D objects to create a sense of depth and realism (or a deliberate stylized effect). It determines how an object’s surfaces look under lighting, which parts are bright and dark, and how colors change in light or shadow so that flat digital models appear solid and lifelike. In animation, video games, and VFX, various shading techniques achieve different visual styles, from photorealistic to cartoonish.
In simple terms, shading is about making flat things look not-so-flat. It’s how we trick the eye into seeing depth and texture on a 2D screen.
In the digital world, shading is the math and artistry that determines lights and shadows on 3D models. By calculating how light hits a surface and how that surface responds (is it shiny, dull, translucent?), the computer paints the right highlights and shadows, giving objects volume and mood. Shading makes digital scenes look immersive.
Here’s a breakdown of basic shading techniques found in film, animation, VFX, and video games:
Flat Shading
Definition: Flat shading is the most basic technique, lighting each polygon of a 3D model with a single solid color.
Technical Overview: It’s very fast, but it makes objects look blocky since every face is uniformly lit, and sharp edges appear between faces.
Examples: The pioneering CGI sequences in Tron (1982) were rendered with flat shading, meaning each 3D surface was given a single solid color. This approach resulted in a distinctive abstract look with no smooth shading transitions, as the technology of the time relied on flat, untextured colors for the film’s computer-world visuals.
Early 3D games like Star Fox (1993) and Elite (1984) (the Amiga version) used flat shading, giving their spacecraft and characters a distinctly angular, low-poly look.
Gouraud Shading
Definition: Gouraud shading smooths out lighting across a 3D surface by calculating brightness at each polygon’s corners (vertices) and blending the colors across it.
Technical Overview: This method was more advanced than flat shading and much faster to compute than per-pixel shading, though it could miss shiny highlights if they fell in the middle of a polygon (away from any vertex).
Examples: The Last Starfighter (1984) – This film’s space battle CGI was composed of models lit with Gouraud shading (smoothly interpolating vertex lighting).
Also, many late-90s 3D games (like Super Mario 64 in 1996) used Gouraud shading to make characters and worlds look softer and more natural.
Phong Shading
Definition: Phong shading takes smooth lighting further by calculating light at every pixel on a surface, not just at the vertices. It produces seamless lighting and captures shiny highlights in the right spots.
Technical Overview: It basically asks each pixel how it faces the light, ensuring highlights show up where they should and shadows transition smoothly. Phong shading was heavier to compute than Gouraud back in the day, but it became standard as hardware improved.
Example: Toy Story (1995), as the first feature-length CGI animation, used more advanced lighting models, such as Phong shading, for its characters and objects.
Halo: Combat Evolved (2001) showcased Phong shading in real time: Master Chief’s armor gleamed under lights, and environments had smooth, realistic lighting.
Blinn-Phong Shading
Definition: Blinn-Phong is a tweak of the Phong model that gives similar visuals but is more efficient to compute. For years, it became the default shading method in many games.
Technical Overview: It calculates specular highlights using a “halfway” vector (between the viewer’s direction and the light’s direction) to simplify the math. This yields slightly broader but still realistic highlights on surfaces.
Examples: Most 1990s CGI films used the Blinn–Phong model (Jim Blinn’s improvement to Phong) for lighting. For example, Pixar’s early productions, such as A Bug’s Life (1998), used Blinn–Phong shading to portray materials with convincing depth and specular highlights, moving beyond the flat look of earlier animation:
This was the standard approach before physically-based shading became common.
Also, almost every game in the 2000s used Blinn-Phong shading by default. This model created the subtle sheen on characters’ armor or the gleam on cars in those games. It was also common in CGI for movies during that era until the move to more physically accurate shading.
Cel Shading
Definition: Cel shading makes 3D graphics look flat and hand-drawn, using solid areas of color instead of smooth gradients.
Technical Overview: A cel shader takes the lighting on a surface and reduces it to a few distinct tones. For example, a character might be one solid shade on the lit side and a darker shade on the shadow side, with a sharp border between them. The result is a 3D scene that looks like a 2D cartoon.
Example: In The Iron Giant (1999), the titular Iron Giant was a CGI model rendered with cel-shading to blend with the hand-drawn world.
Also, the video game The Legend of Zelda: The Wind Waker (2003) famously used cel shading to give its 3D world bold, flat colors and a charming cartoon look.
Toon Shading
Definition: Toon shading is the same concept as cel shading—making 3D look like a cartoon—but the term often implies the full comic-book style (flat colors plus bold outlines and stylized details).
Technical Overview: Many 3D software packages offer a “toon shader” that automatically applies flat color bands (like cel shading) and adds ink-like edge lines around objects.
Examples: The Dragon Prince (2018 series) is an excellent example of modern toon shading in animation. It uses a cel-shaded 3D art style – essentially toon-shaded CG – to mimic the look of 2D anime.
Borderlands (2009) is the best example of toon shading in action that I can think of within the video game world. Its world and characters are rendered with flat colors and thick black outlines, so playing it feels like stepping into a graphic novel.
Physically Based Rendering (PBR)
Definition: Physically Based Rendering (PBR) uses real-world lighting and material physics to achieve photorealism. Surfaces are defined by metalness and roughness, meaning they react to light as they would in reality.
Technical Overview: PBR uses formulas that obey the laws of physics (conserving energy, realistic light scattering, etc.). If you set up a material with the correct values (for example, if a surface is fully metallic and very rough), it will look correct under any lighting environment without special tweaking.
Examples: Disney’s animated feature, Big Hero 6 (2014), used a fully physically based rendering pipeline for its CGI. Using the Hyperion renderer (a new PBR path-tracer developed at Disney), Big Hero 6 achieved highly realistic lighting and materials. Every surface in the film—from Baymax’s vinyl body to city buildings—obeyed accurate physical light properties, marking a shift to more lifelike shading in animation.
PBR is everywhere nowadays. It’s why metals glint in Red Dead Redemption 2, leather looks worn, and water behaves realistically, and why Iron Man’s CGI suit in the Avengers films reflects light just like a real metal suit.
Subsurface Scattering
Definition: Subsurface scattering (SSS) is a shading technique for slightly translucent materials like skin or wax. It simulates light entering a material, bouncing around inside, and exiting nearby, which gives these materials a soft glow and a lifelike quality. Here’s a good video explaining it in more detail:
Technical Overview: Light penetrates beneath the surface and diffuses, making lit areas softer and causing thin parts (like ears) to glow when backlit. Even a subtle SSS effect makes characters and materials look far more convincing.
Examples: A breakthrough use of SSS is seen on Gollum’s skin in The Lord of the Rings: The Two Towers (2002). In bright scenes, light visibly filters through his ears and nostrils, giving him realistic fleshiness.
Shrek 2 (2004) was a milestone in using subsurface scattering (SSS) for animated characters. DreamWorks introduced SSS in Shrek 2 to simulate light passing through skin and other translucent materials. For example, Shrek’s green skin was rendered with bounce lighting under the surface (notably his ears glow when backlit), using this new technique to add softness and realism that wasn’t present in the first film.
Ambient Occlusion
Definition: Ambient occlusion (AO) adds soft shadows in the little nooks and crannies of a scene to simulate how ambient light is partially blocked in those areas. It darkens corners, creases, and where surfaces touch, adding depth that normal lighting alone might miss.
Here’s a video that explains it well and includes some examples:
Technical Overview: AO isn’t tied to a single light source; it’s about the overall ambient illumination. The renderer figures out how much open space or sky each point can “see”—if a spot is tucked away, it gets shaded darker.
Example: Pixar’s The Incredibles (2004) first extensively used ambient occlusion to enhance shading. They added an extra AO pass (via ray tracing) to generate soft shadowing in creases and contact areas, grounding the cartoonish world with subtle realism. In fact, The Incredibles marked Pixar’s first widespread use of ray-traced ambient occlusion, helping scenes gain depth with gentle darkening in corners and where objects meet.
Film VFX artists add AO passes to give CGI creatures those subtle contact shadows that help them blend into real scenes.
Crytek’s Crysis (2007) is one of the most famous examples of ambient occlusion in video games: with AO turned on, every crevice and corner looked naturally shadowed. This, in turn, made the game require a beefy computer and sparked the famous meme “but will it run Crysis?” when talking about new gaming setups.
Stylized or Non-Photorealistic Shading
Definition: Stylized or non-photorealistic (NPR) shading is any shading method that forsakes realism for an artistic effect. The goal is to make 3D scenes look like a painting, drawing, or graphic rather than a photo.
Technical Overview: NPR techniques are diverse. Some use flat colors and outlines like a comic book, others apply brushstroke-like textures or cross-hatching to emulate fine art. They all override normal lighting to prioritize style over realism.
Example: Spider-Man: Into the Spider-Verse (2018) is a prime example. It used a mix of NPR techniques—like halftone dots and bold outlines—to make every frame look hand-drawn, as if a comic book had come to life.
Why Shading Matters
When done well, shading is often invisible to the audience (or at least not something you think about), but it’s critical to how an image looks. It gives 3D objects their shape, depth, and material feel—a character’s face looks round and alive, metal looks shiny, and fabric looks soft because of shading. Without it, even detailed models would appear flat and lifeless.
Shading also sets the mood: harsh, sharp-edged shadows can make a scene feel tense or dramatic, while soft, even lighting gives a warm feel.
For creators, knowing different shading methods gives us more control over the final look. If you want gritty realism, you can use realistic lighting and shadows; for a playful cartoon vibe, you can use flat colors and simple shading.
Shading also makes all the elements in a shot feel cohesive—a CGI creature or spaceship will only look convincing next to real actors if its shading matches the scene’s lighting. In short, shading is a technical tool that, when used artfully, brings scenes to life.
Summing Up
Shading techniques have evolved from the flat polygons of early 3D to today’s physics-based renderers. Each method we’ve discussed is like a different brush in an artist’s toolkit. For anyone working in these fields, knowing these techniques means you can pick the right tool to get the look you want in your projects.
In the end, shading isn’t just a technical step; it’s a creative choice that shapes a project’s final look and feel. It’s how artists turn plain 3D models into images that evoke emotion and atmosphere. Shading is the key to making it happen, whether aiming to fool the eye with realism or dazzle with a unique style.
Read Next: What Does an Animator Do? Roles, Skills, & the Animation Pipeline
