The World of Rendering Terminology


With the ever-increasing demand for sophisticated final products in 3D and animation, rendering has become one of the most sought-after techniques. Used as an advanced fine-tuning in graphics and modeling, this creative standard is used widely to produce precise and artistic final images. Rendering is considered the ‘final step’ in 3D computing and graphic design and has fast become essential in producing sophisticated results.

Rendering is used across the board in video games, simulators, movies, visual effects and many more. Its actual process requires a heavy usage of GPU (Graphics Processing Unit), which supports the CPU in performing intricate calculations used by the renderers. When selecting rendering software, one must be aware of the differences between biased and unbiased renderers. Biased renderers are more refined in their work in comparison to the unbiased ones. Unbiased rendering will give a more mathematically correct result; however, biased rendering will give a more accurate result with less CPU time. Bearing these differences in mind, one needs to carefully consider the most appropriate render technique for their needs.

We have listed a number of related terminology’s for Rendering below, however, we may have excluded some other terms, nonetheless, you shall find mostly the information below is common language to those that are involved in the professional design, computer-generated imagery (rendering) and graphical presentation.

 Enjoy!

 

Camera:

3D Gizmo: 3D gizmos help you move, rotate, or scale a set of objects along a 3D axis or plane.

Typical 3D Gizmo operations as follows..

                3D Move gizmo-Relocates selected objects along an axis or plane.

                3D Rotate gizmo-Rotates selected objects about a specified axis.

                3D Scale gizmo-Scales selected objects along a specified plane or axis, or uniformly along all 3   axes.

Dolly Camera: Moves the camera to and from the object at which it is pointing.

Dolly Target: Moves the camera’s target to and from the object.

Exposure:  is the amount of time where space or surface is open to the light/sun when making a photograph or a render.

Iso: ISO speed controls the sensitivity of a given space or surface that absorbs the light. The higher the ISO speed, the more sensitive space or surface is to light, e.g. If you were to change your ISO from 200 to 400, you would be making the image twice as bright. In the above example, at an aperture of f/3.5, shutter speed of 1/125th of a second and ISO 200, if you were to increase the ISO to 400, you would need twice less time to properly expose the image.

Viewport: This is a 2D rectangle used to project the 3D scene to the position of a virtual camera. A viewport is a region of the screen used to display a portion of the total image to be shown.

 

Effects:

Brightness: is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception drawn from the luminance of a visual target.

Caustics: In optics, a caustic or caustic network is the envelope of light rays reflected or refracted by a curved surface or object, or the projection of that envelope of rays on another surface.

Depth field: Any out of focus or blurry image can be brought to life by using depth field feature of rendering.

Edge Smoothing: How much anti-aliasing to apply to material edges and bumps.

Fogging: use this feature to test how the light passes through any surrounding.

Fresnel: Pronounced fren-el with a silent s – This is the value of how much of the light rays are being reflected off surfaces vs how much is absorbed. Surfaces viewed at an angle reflect more on incoming light compared to surfaces more directly facing your eye or camera.

Gamma Correction: Controls the overall brightness of an image. Images which are not properly corrected can look either bleached out or too dark.

Luminance: is a photometric measure of the luminous intensity per unit area of light traveling in a given direction. It describes the amount of light that passes through, is emitted or reflected from a particular area, and falls within a given solid angle.

Motion-blur: High-speed motion of camera can make objects appear blurry; motion blur can help make changes here and there.

Reflection: Helps in making changes in highly glossy reflections and mirror-like images. Accomplished in ray-traced rendering. By following a ray from the eye to a mirror and then calculating the process until no surface or non-reflective surface is on a shiny surface like wood or tile can add to the photorealistic effects of a 3D rendering.

Some terms associated with Reflection effects as follows..

Blurred– A blurred reflection means that tiny random bumps on the surface of the material cause the reflection to be blurry.

Glossy– This term can be misused. Sometimes, it is a setting which is the opposite of blurry (e.g. when “glossiness” has a low value, the reflection is blurry). However, some people use the term “glossy reflection” as a synonym for “blurred reflection”. Glossy used in this context means that the reflection is actually blurred.

Metallic– A reflection is metallic if the highlights and reflections retain the colour of the reflective object.

Polished– A polished reflection is an undisturbed reflection, like a mirror or chrome.

Refraction: If a light is bending and is transparent one can easily use rendering for improving the image. 

Shading: This feature is used to adjust the brightness and colour of the surface with lighting.

Shadows: It helps in creating the effects of obstructing light.

Smoothing: Is the term used to smooth out faceted (unwanted flat surfaces).

Soft shadow: It helps in tweaking the obscurity induced by a partial light source. 

Translucency: Used for any scattered light that is hindering the image or any surface area.

Transparency: Tweaks can be made in the image with optics and graphics if the sharp light is passing through any object in the image.

Maps:

Ambient Map: Also known as an AO map is a grey image with white indicating areas that should receive full indirect lighting, and black indicating no indirect lighting.

Bump- mapping: A way of changing or improving any irregularity on the surface or the image.

Diffuse Map: Is the most common kind of texture map which defines the colour and pattern of a 3d model or object where mapping the diffuse colour is like painting an image file (photograph of bricks)onto the surface of an object.

Displacement Map: This technique helps to bring forth depth and detail in any surface, particularly allowing self-shadowing, silhouettes and self-occlusion to portray a 3d surface effect.

Normal Map:  Is a texture that contains depth information of a given surface. They don’t have impact of performance or change the structure of a model. Each pixel represents a normal vector which has 3 colours which represent the direction of the normal vector.

Specular Map: are the maps you use to define a surface’s shininess and highlight colour  The higher the value of a pixel (from black to white), the shinier the surface will appear in-game.

Texture Mapping: With this, one can add texturing details to the surfaces of their model or the scene.

Tone Mapping: Tone mapping is a technique used in image processing and computer graphics to map one set of colour to another to approximate the appearance of high- dynamic-range images in a medium that has a more limited dynamic range.

Lighting:

Ambient occlusion: A shading and rendering computer graphics technique that helps in calculating the amount exposed to ambient lighting in any scene.

Area Lights/LEM: is defined by a rectangle in space. Light is emitted in all directions uniformly across their surface area, but only from one side of the rectangle.

Denoiser: A way of decreasing or removing the background sounds from any videos, radio signals, tapes and many more.

Diffraction: One can easily transform interfering, spreading and bending light that disrupts any image.  

Diffuse: Is the reflection of light, waves or particles from a surface which is scattered at many angles rather than at just one angle, similar to the specular reflection

Directional Light: very useful for creating effects such as sunlight in your scenes. Behaving in many ways like the sun, directional lights can be thought of as distant light sources which exist infinitely far away.

Emissive/Neon Light: Like Area Lights, Emissive materials emit light across their surface area. They contribute to the bounced light and associated properties such as colour and intensity ‘Emission’ is a property of the Standard Shader which allows static objects in our scene to emit light.

Global or Indirect illumination: Lights reflected from the surface is used to highlight an object in the image.

Gobo Lighting: is a stencil or template placed inside or in front of a light source to control the shape of the emitted light. Lighting designers typically use them with stage lighting instruments to manipulate the shape of the light cast over a space or object—for example, to produce a pattern of leaves on a stage floor.

IES (Illuminating engineering society): Show your distinct creativity by using IES for lighting effects with varied shapes and any physically defined forms.

Indirect Lighting: Lighting provided by reflection usually from wall or ceiling surfaces. In daylight, this means that the light coming from the sky or the sun is reflected on a surface of high reflectivities like a wall, a window sill or a special redirecting device

Noise: Set frequency, select scales, determine the variations, control the magnitude of the surface with this amazing feature.

Point Light: is located at a point in space and sends light out in all directions equally

Projector Light: projecting an image or Gobo texture onto a screen or other surface for viewing.

Spot Light: has a specified location and range over which the light falls off.

Subsurface scattering: also known as subsurface light transport (SSLT), is a mechanism of light transport in which light penetrates the surface of a translucent object, is scattered by interacting with the material and exits the surface at a different point.

Volumetric lighting: is a technique used in 3D computer graphics to add lighting effects to a rendered scene. It allows the viewer to see beams of light shining through the environment; seeing sunbeams streaming through an open window is an example of volumetric lighting, also known as crepuscular rays. The term seems to have been introduced from cinematography and is now widely applied to 3D modeling and rendering especially in the field of 3D gaming.

Rendering:

Animation is when images or objects are manipulated to appear as moving images. In traditional animation, images are drawn or painted by hand on transparent celluloid sheets to be photographed and exhibited on film. Today most animations are made with computer-generated imagery (CGI).

Bias: You have manual control over how the render engine interprets your scene, by how well lighting is cast, shadows and bouncing light calculations (radiosity / indirect lighting)–and other effects such as secularity. In other words, biased means “limited”–and you set the limit.

CPU Rendering: A rendering process that is not dependent upon graphics hardware, such as a graphics card. CPU rendering takes place entirely in the CPU. (Central Processing Unit)

GPU Rendering: A rendering process that uses the power of GPU (Graphics Processing Unit) for rendering, instead of CPU (processor). … GPU rendering is incredibly fast and less power hungry.

Clay Rendering: is an effective solution to show a model, and especially its topology. Every object of the scene is untextured and is defined by only one material: a warm grey matte, which resembles clay. The result is a monochromic picture

 

Line Antialiasing: Use this option to smooth the edge display in the 3D Scene.

Non- photorealistic rendering: One can make pictures or images more artistic with rendering.

OpenGL: Uses the systems graphics card through OpenGL to provide a faster working environment. Performance can depend on the card and the data amount in the environment. This mode is faster than the Software mode but does not offer the advanced graphics performance of the Advance OpenGL/Direct 3D Mode

OpenGL Advanced/Direct 3D/OpenGL2: This is the best performance mode offered. It will use the system OpenGL/OpenGL2 card or Direct3D depending on the better performance determined by the application. Note: You can specify OpenGL, OpenGL2 or DirectX as the rendering option to best suit your machine configuration. Various real-time rendering options will change availability based on the rendering mode specified.

Real-Time Rendering: is calculated and displayed in real time, at rates of approximately 20 to 120 frames per second. In real-time rendering, the goal is to show as much information as possible as the eye can process in a fraction of a second.

Resolution: is the number of pixel columns and pixel rows in an image or on your display. The most common display resolutions today are: 1280×720 (720p), 1920×1080 (1080p), 2560×1440 (1440p), and 3840 x 2160 (4K or ‘ultra-HD’)

Unbiased: will not settle for anything less than 100% correct real-world calculations, meaning no manual control. An unbiased render engine will simply calculate ALL the data, even things you hardly see–those subtle small nuances that can make a real difference.

Volumetric Rendering: is a set of techniques used to display a 2D projection of a 3D dataset which is a group of 2D slice images.

Render-man: One among the most popular and oldest rendering high-end solutions which are based on the Reyes algorithm. This is majorly used for big productions and a team together can produce miracles with it.   

Images:

Alpha Channel: is the process of combining an image with a background to create the appearance of partial or full transparency. It is often useful to render image elements in separate passes, and then combine the resulting multiple 2D images into a single, final image called the composite.

Bmp: also known as bitmap image file or device independent bitmap (DIB) file format or simply a bitmap, is a raster graphics image file format used to store bitmap digital images, independently of the display device (such as a graphics adapter), especially on Microsoft Windows and OS operating systems.

The BMP file format is capable of storing two-dimensional digital images both monochrome and color, in various color depths, and optionally with data compression, alpha channels, and colour profiles.

HDRI – IBL: High-dynamic-range imaging or Image Based Lighting is a high dynamic range technique used in Computer Graphics Imaging and photography to reproduce a greater dynamic range of luminosity than is possible with standard digital imaging or photographic techniques.

Jpeg/Jpg:  “Joint Photographic Experts Group” is a standard image format for containing lossy and compressed image data. This unique compression feature allows JPEG files to be used widely on the Internet, Computers, and Mobile Devices. Also, a large number of JPEG image files can be stored in minimum storage space. JPEG files can also contain high-quality image data with a lossless compression. This format does not support transparency.

Pixel: A pixel is the most basic unit of a digital image—a tiny dot of colour

Png: “Portable Network Graphics” is a lossless file format designed as a more open alternative to Graphics Interchange Format (GIF).  Unlike JPEG, which relies on DCT compression, PNG uses LZW compression — the same as used by GIF and TIFF formats. Boiled down, PNG’s two-stage LZW compression takes strings of bits contained in the image’s data, matches those longer sequences to accompanying shortcodes held in a dictionary (sometimes referred to as a codebook) that is stored within the image file. The result is a smaller file that maintains high quality.

Tiff: “Tagged Image File Format” abbreviated TIFF or TIF, is a computer file format for storing raster graphics images, popular among graphic artists, the publishing industry, and photographers. TIFF is widely supported by scanning, faxing, word processing, optical character recognition, image manipulation, desktop publishing, and page-layout applications.

 

We trust you find our blog of render terms a useful source of reference – Happy Rendering!

 

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