Rendering Computer Graphics: Exploring Visual Realism: Insights into Computer Graphics

By Fouad Sabry

What is Rendering Computer Graphics

Rendering or image synthesis is the process of generating a photorealistic or non-photorealistic image from a 2D or 3D model by means of a computer program. The resulting image is referred to as the render. Multiple models can be defined in a scene file containing objects in a strictly defined language or data structure. The scene file contains geometry, viewpoint, textures, lighting, and shading information describing the virtual scene. The data contained in the scene file is then passed to a rendering program to be processed and output to a digital image or raster graphics image file. The term "rendering" is analogous to the concept of an artist's impression of a scene. The term "rendering" is also used to describe the process of calculating effects in a video editing program to produce the final video output.

How you will benefit

(I) Insights, and validations about the following topics:

Chapter 1: Rendering (computer graphics)

Chapter 2: Global illumination

Chapter 3: Ray tracing (graphics)

Chapter 4: Scanline rendering

Chapter 5: Rasterisation

Chapter 6: Ray casting

Chapter 7: Volume rendering

Chapter 8: Non-photorealistic rendering

Chapter 9: Real-time computer graphics

Chapter 10: Computer graphics

(II) Answering the public top questions about rendering computer graphics.

(III) Real world examples for the usage of rendering computer graphics in many fields.

Who this book is for

Professionals, undergraduate and graduate students, enthusiasts, hobbyists, and those who want to go beyond basic knowledge or information for any kind of Rendering Computer Graphics.

• Language: English
• Publisher: One Billion Knowledgeable
• Release date: May 14, 2024

Book preview

Chapter 1: Rendering (computer graphics)

Using a computer software, rendering or image synthesis is the process of generating a photorealistic or non-photorealistic image from a 2D or 3D model. The rendered image is known as the render. A scene file containing objects in a precisely specified language or data structure can define many models. The scene file contains information on the scene's geometry, viewpoint, texture, lighting, and shading. The scene file's data is then sent to a rendering program for processing and output as a digital image or raster graphics image file. The term rendering corresponds to an artist's interpretation of a scene. Rendering also refers to the process of computing effects in a video editing tool to produce the final video output.

Rendering is one of the most important subtopics of 3D computer graphics, and it is always interconnected with the others in practice. It is the final significant step in the graphics pipeline, and it gives models and animation their final appearance. Since the 1970s, as the sophistication of computer graphics has increased, the theme has become more distinct.

Rendering has applications in architecture, video games, simulators, film and television visual effects, and design visualization, each of which employs a unique combination of features and approaches. There are numerous renderers available for use. Some are integrated into larger modeling and animation software packages, while others are free open-source projects. A renderer is an intricately crafted program based on various fields, such as light physics, visual perception, mathematics, and software engineering.

Even though the technical details of rendering technologies vary, the graphics pipeline of a rendering device such as a GPU handles the general issues of creating a 2D image on a screen from a 3D representation contained in a scene file. A GPU is a device designed specifically to aid a CPU in completing sophisticated rendering computations. The rendering software must solve the rendering equation for a scene to appear relatively realistic and predictable under virtual illumination. The rendering equation does not account for every lighting phenomenon, but rather serves as a basic lighting model for computer-generated pictures.

Scenes in 3D graphics can be rendered in advance or generated in real time. Pre-rendering is a slow, computationally costly technique that is often used for the creation of movies, in which scenes can be prepared in advance, whereas real-time rendering is typically used for 3D video games and other applications that must generate scenes in real time. Accelerating 3D hardware can enhance real-time rendering performance.

When the pre-image (often a wireframe sketch) is complete, rendering is used to add bitmap or procedural textures, lights, bump mapping, and the relative location of objects. The end product is a finished image that the consumer or intended audience observes.

Several images (frames) must be produced and stitched together in an animation-making tool in order to create a movie animation. The majority of 3D picture editing applications can do so.

A rendered image can be comprehended based on its visual characteristics. Research and progress in rendering has been largely inspired by the search for efficient simulation techniques. Some are directly related to particular algorithms and methods, while others are generated collaboratively.

Shading is how the hue and luminance of a surface change as a function of lighting.

Texture-mapping — a technique for imparting surface detail

Bump-mapping is a technique for replicating small-scale surface roughness.

Fogging/participating medium — the dimming of light as it passes through an opaque atmosphere or air

Shadows are the result of blocking light.

Variable darkness resulting from partially occluded light sources.

Reflection — highly reflective or mirror-like reflection

Sharp transmission of light through opaque objects.

Translucency - greatly dispersed light transmission through opaque objects

Refraction is the light-bending phenomenon associated with transparency.

Diffraction is the ray-disturbing bending, spreading, and interference of light travelling through an object or aperture.

Indirect lighting refers to surfaces that are lighted by light reflected from other surfaces as opposed to a direct light source (also known as global illumination)

Caustics (a type of indirect illumination) is the reflection of light off a glossy object or the focussing of light through a transparent object to create dazzling highlights on another object.

Depth of field — when objects are too far in front of or behind the object in focus, they appear hazy or out of focus.

Objects appear hazy because of high-speed motion or the movement of the camera.

Non-photorealistic rendering — sceneries rendered in an artistic way to resemble a painting or drawing

Numerous rendering methods have been studied, and rendering software may use a variety of ways to produce a final image.

Tracing each and every speck of light in a scene is nearly always impractical and would need an enormous amount of effort. Even tracing a piece large enough to make an image requires excessive time if the sampling is not carefully limited.

Consequently, several informal families of more effective light transport modeling algorithms have evolved:

Rasterization, which includes scanline rendering, projects scene objects onto an image plane physically, without advanced optical effects; ray casting analyses the scene as perceived from a particular vantage point, calculating the observed image using simply geometry and the most fundamental optical equations of reflection intensity, and maybe employing Monte Carlo approaches to decrease artifacts; ray tracing is comparable to ray casting, but it incorporates more complex optical simulation and typically uses Monte Carlo techniques to get more realistic results at speeds that are typically orders of magnitude quicker.

route tracing is similar to ray tracing in that it focuses on providing realistic lighting effects and is capable of unbiased rendering, but it is far more resource-intensive.

Radiosity, the fourth type of light transport approach, is typically not implemented as a rendering technique; rather, it calculates the flow of light as it leaves the light source and lights surfaces. Typically, these surfaces are displayed to the display using one of the other three methods.

Most sophisticated software combines two or more of the strategies to achieve satisfactory results at a reasonable price.

Image order algorithms, which loop over pixels of the image plane, are distinguished from object order algorithms, which iterate over scene objects. Object order is typically