Alpha_1 User's Manual

Options

Render and ray provide many options available to the user. There are two types of controls: switches and parameters. Switches are passed to the program at run time as part of the command execution. Parameters, on the other hand, are part of the input data to the program. For example: the type of lighting model used to do the shading is chosen by a render program switch, but the number of light sources and their respective positions are parameters, or part of the input data. Switches and parameters will be described in separate sections although they must interact and be consistent for correct results.

The parameters that we will be concerned with are the ones that affect the shading of the image. These parameters include the color, transparency, and material properties of the surfaces rendered as well as the positions of the light sources. Each parameter can be created by the user using c_shape_edit commands and writing the objects to a file, just like the geometric data.

The following sections describe the various switches and shading parameters in detail including their meaning, specification, and default values. Examples are provided on how to run the render program and use the flags and parameters. Lastly, two sections are provided for quick reference. One gives a brief description of the various render switches, and the other describes the syntax for specifying the various shading parameters.

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