Rendering

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What Is Rendering?

Rendering refers to the process of generating a two-dimensional (2D) or three-dimensional (3D) image from a model using specialized computer software applications. Rendering is widely used in architecture, video games, computer-generated imagery (CGI), animated movies, simulators, and design visualization. Today, rendering also plays a key role in artificial intelligence (AI), virtual reality (VR), augmented reality (AR), and medical imaging.

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Rendering techniques and features vary depending on the project. While rendering improves efficiency in design, it comes at a cost. High-quality rendering can be time-consuming and requires significant computer processing power.

While most commonly associated with generating models, the term rendering has meaning in other technology contexts. For example, in web development, rendering refers to how content is processed and displayed in a web browser (i.e., client or server-side rendering). In programming, the definition of rendering refers to generating and displaying output, such as visual elements in graphical user interfaces (GUIs).

Key Takeaways

  • Rendering refers to the process of generating a 2D or 3D image from a model using specialized software.
  • Rendering is widely used in architecture, video games, computer-generated imagery, animated movies, artificial intelligence, and medical imaging.
  • High-quality rendering can be time-consuming and requires significant computer processing power.
  • In video games, real-time rendering creates images instantly for players to interact with.
  • Pre-rendering is used in animated films where visual quality is more important than speed.

How Rendering Works

Before rendering, 2D and 3D productions go through many stages of production, including concept development, storyboarding, model creation, texturing, rigging, animation, and editing. Each step builds upon the previous one, ensuring that the final render produces a high-quality result.

Rendering is the final step in producing computer graphics, where colors, lighting, textures, and shadows are calculated to generate a realistic or specific style of visual output.

Rendering Types

There are two main rendering categories: real-time rendering and pre-rendering. The difference between the two is how fast images are processed and displayed.

Real-time rendering
Prominent rendering technique used in video games and interactive graphics, where images must be created instantly as the user interacts with the environment. It relies on a dedicated graphics processing unit (GPU) and techniques like pre-compiling data to improve performance.
Pre-rendering
Pre-rendering, sometimes called offline rendering, is used in environments where visual quality is more important than speed. Unlike real-time rendering, images are processed in advance using multi-core central processing units (CPUs) instead of GPUs. This rendering technique is common in animated films, CGI effects, and architectural visualization, where photorealism needs to be at the highest standard possible.

Rendering Process

While the specifics of the rendering process differ between real-time rendering and pre-rendering, the general step-by-step process is as follows:

  1. Create a model

    A 2D or 3D model is designed using specialized software.
  2. Set up the scene

    Objects, lights, textures, and camera angles are arranged.
  3. Apply textures

    Surfaces are given colors, patterns, and reflections.
  4. Add lighting & shadows

    Light sources are placed to create depth and realism.
  5. Process rendering calculations

    The computer determines each pixel’s color, brightness, and effects.
  6. Generate final output

    The completed image or animation is displayed/saved.

Rendering Components

Rendering software includes built-in tools for managing models, textures, lighting, and other components that designers and animators use to create realistic images or animations.

Examples of rendering components include:

  • Anti-aliasing
  • Camera angles
  • Depth of field
  • Lighting
  • Materials
  • Models
  • Reflections
  • Shadows
  • Textures

Rendering Techniques

Rendering techniques determine how images are generated from 3D models. They use rendering algorithms, which are mathematical formulas that define how each technique processes an image. Some of them prioritize speed for real-time graphics, while others focus on realism.

A few examples of rendering techniques include:

  • Ambient occlusion
  • Cel shading
  • Global illumination
  • Non-photorealistic
  • Path tracing
  • Photon mapping
  • Rasterization
  • Ray tracing
Three humanoid helmets displayed side by side, showcasing different rendering techniques: Path Traced, Ray Traced, and Rasterization.
Comparing path tracing, ray tracing, and rasterization. Source: NVIDIA Blog

Rendering Uses

Video games
Generates interactive and responsive environments at high frame rates instantly using real-time rendering. Rendering in video games relies on dedicated graphics hardware to process visuals. Techniques used in video games include rasterization, real-time ray tracing, and baked lighting.
AI-powered image generation
AI image generators use real-time and pre-rendering to create realistic or stylized visuals from text or other inputs. AI systems use deep learning to enhance details, upscale images, and synthesize new visuals. Techniques used in AI image generators include neural rendering, AI upscaling, and GAN-based image synthesis.
Medical imaging
Generates 2D and 3D visualizations from medical scans (e.g., MRI and CT scans). Rendering techniques used in medical imaging include volume rendering, ray casting, and surface reconstruction.

The Bottom Line

The definition of rendering refers to the process of generating a 2D or 3D image from a model using specialized computer software. Rendering is widely used in architecture, video games, CGI, animated films, and medical imaging – with applications extending to AI, VR, and AR.

There are two main rendering categories. Real-time rendering generates images instantly for interactive environments like video games, while pre-rendering prioritizes high-quality visuals in CGI and animation. Different rendering techniques (e.g., path tracing, ray tracing, and rasterization) rely on rendering algorithms to simulate lighting, textures, and shadows.

Even AI-powered image generation relies on rendering, leveraging deep learning techniques like neural rendering and AI upscaling to create images. Keep in mind that high-quality rendering can be costly as it requires significant computing processing power and time.

FAQs

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References

  1. What Is Path Tracing? (NVIDIA Blog)
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Vangie Beal
Technology Expert
Vangie Beal
Technology Expert

Vangie Beal is a digital literacy instructor based in Nova Scotia, Canada, who joined Techopedia in 2024. She’s an award-winning business and technology writer with 20 years of experience in the technology and web publishing industry. Since the late ’90s, her byline has appeared in dozens of publications, including CIO, Webopedia, Computerworld, InternetNews, Small Business Computing, and many other tech and business publications. She is an avid gamer with deep roots in the female gaming community and a former Internet TV gaming host and games journalist.