Rendering is defined as the process of generating a synthetic image of a scene given a complete description of its geometry and other characteristics.
The process of shaded image generation is divided into two distinct stages.
The first stage is known as visible surface processing, during which the renderer establishes, for every pixel of the image, what surface or surfaces are visible. When this information is available, the second stage of the rendering process evaluates the contribution made by each of the visible surfaces to the final shade of the displayed pixel.
This second step, known as shading, encompasses all of the calculations that must be performed in order to determine each pixel's intensity. These include accounting for every light source in the scene and calculating how much light falls on the visible surfaces, as well as determining the color of the visible surface.
solidThinking supports a number of choices for visibility processing in the form of alternative rendering methods.
Typically, each rendering method is designed to fulfill specific requirements and will provide a unique algorithmic solution for visibility processing. Depending upon the quality of image that is required and the features that it contains, solidThinking utilizes alternative methods of shading operation in order to maximize performance in various configurations.
Rendering methods can be summarized as follows:
Wireframe rendering
The simplest form of rendering. Vector output showing all the edges of the geometry with no consideration to whether a particular edge should be visible or obscured by other geometry.
Hidden line rendering
Vector output showing only those lines which would be visible from the current view point (i.e., lines hidden by other surfaces are removed).
Flat shaded rendering
Each surface is assumed to be opaque with a single, uniform color. Curved surfaces are approximated by a mesh of polygonal facets. In the shaded image, each facet is painted uniformly with an average color.
Gouraud shaded rendering
Each surface is assumed to be opaque with a single, uniform base color. Curved surfaces are approximated by a mesh of polygonal facets, and in the shaded image, colors are calculated at each vertex of each facet, then, these colors are blended across the facets to create smooth shading of curved surfaces. It is named after his French originator, Henry Gouraud.
Phong shaded rendering
Each surface is assumed to be opaque with a single, uniform base color. Curved surfaces are approximated by a mesh of polygonal facets, and in the shaded image, normal vectors at the vertices of each facet are interpolated and a shade is calculated independently for each pixel. This technique, known as Phong interpolation, enables smooth shading of curved surfaces and is able to render precise, realistic specular highlights. It was originated by Phong Bui-tuong.
Scanline preview rendering
Shaded rendering with full texturing features using the preview scan-line renderer. The geometry is sampled at a rate of one sample per rendered pixel, so that object silhouettes take on a jagged appearance. Transparency shading is not supported in this method.
Scanline full rendering
The model is rendered as a fully shaded and textured, anti-aliased image. The geometry is sampled at a sufficient rate to eliminate aliasing artifacts on object silhouettes.
Raytrace preview rendering
Shaded rendering with full texturing features using the preview ray tracer renderer. The geometry is sampled at a rate of one sample per rendered pixel, so that object silhouettes take on a jagged appearance.
Raytrace full rendering
The model is rendered as a fully shaded and textured, anti-aliased image using the full ray tracer renderer. The geometry is sampled at a sufficient rate to eliminate aliasing artifacts in regions of high intensity gradient.