THREE-DIMENSIONAL RENDERING

This refers to an automatic process through which 3Dimensional computer graphics convert 3D frame models to images that are in 2D form while retaining the photorealistic effects as well as retaining the non-photorealistic effects. Rendering is practically the last stage involved in creating 2D images and animations from a scene that has been prepared. It is compared to filming of a photographed scene upon completion of a real life setup. With time, many specialized and different rendering methods are being developed. They range from non-realistic wireframe method, through the polygon based method to advanced methods like ray tracing and radiosity. The time required by the rendering process may range from milliseconds to several days for one image or frame. Some rendering methods are explained below.
Real time
The rendering of interactive media like simulations or video games is worked out and demonstrated only through real time at rates between twenty to two hundred frames every second. The main aim of real-time rendering is to display much information possible as one can see and process within a second. Another consideration is to achieve the highest possible levels of Photorealism that the human eye can see and create illusions of the movements. Rendering software is used to simulate visual effects like motion blur, lens flares and field depth, and are aided by a computer’s GPU.
Non real-time
This refers to the animation of media that is non-interactive like feature films or videos, and the rendering speed here is relatively lower. Higher image qualities are obtained by leveraging the processing power that is often limited. Rendering times may vary from several days when rendering complex scenes to few seconds when dealing with non-complex scenes. This technique is widely employed artistic works to simulate natural effects. Some techniques include volumetric sampling, caustics, subsurface scattering and particle systems.
Reflection models
Reflection models together with shading models describe how a surface appears. Reflection/scattering refers to the way light interacts with a given surface at any point, while reflection refers to the variation of material properties across the given surface. Some popular techniques in reflection rendering include, flat shading, Gouraud shading, texture mapping, cell shading, phong shading and bump mapping. Shading explains the different scattering functions and where they are applied.
Transport
This refers to the way illumination in any given scene moves from one point to another. The movement of this light is highly dependent on visibility.
Projection
For a display device to display a shaded object in 2D, that object has to be flattened from 3D images to 2D images. This “flattening” process is what is referred to as 3D projection. The main idea of perspective projection ensures that objects which are far from the eye are made to be smaller as compared to those closer. If the perspective is not present, then the dilation constant automatically becomes one. A high dilation constant may cause some “fisheye” effect, which distorts the image.