# Introduction to RenderWorld

RenderWorld's rendering algorithms are anchored in the laws of physics. This means that the description of the environment is at a relatively high level, each component of the environment is created based on a combination of a relatively few number of parameters and procedural algorithms. The rendering engine handles most of the details of creating and rendering fine structure and evolution. In the RenderWorld Engine, the user does not select colors for the sky or texture maps for the ocean surface. For each object, you specify its position and orientation as a function of time, a few additional global parameters, and stand back. When you choose an atmosphere and put the sun straight overhead, you get a beautiful blue sky. Put the sun a degree below the horizon, and the sky changes to reds, yellows and oranges. Similarly, water waves are described by little more than a wind speed and direction. Additional controls and options allow the user to vary the look of the environment, all the way to creating alien scenescapes.

In this short introduction you will learn how to create and manipulate the input files which control the RenderWorld Engine and define the environment to be rendered. Included with this introduction is a number of examples illustrating each point.

The discussion begins with a section on coordinate systems, and units. One of the options available to the user is to write out any of a sequence of compositing fields - image-like information which can be used to reconstruct the full rendered image from parts, and which provide information about the 3D environment seen by the camera. The discussion shows how the data in the compositing fields can be used to accomplish the reconstruction, and by implication, to allow users to alter individual pieces of the environment and put them all together in a seamless way.

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