How to get started with environmental mapping.

Environmental mapping is a scheme that improves the mapping techniques of chrome and refraction mapping for example to create a 3D configurator. It is useful because raytracing can be very expensive in a reflective environment. Environment Mapping reflect these reflections cheaper and with less loss of accuracy.

Its calculation is independent of the level of detail of the environment. In environment mapping, the object is surrounded by a closed three-dimensional surface onto which the environment is projected. Reflected rays are tracked by the object, hit the surface and are indexed to the map. It is essentially the same as chrome mapping, except that the map consists of an image of the environment as seen from the center of the space to be mapped.

Factors that influence the environment mapping.

For all environment mapping techniques, accuracy depends on the object being positioned in the middle of the surface and the objects in the environment being distant from the objects receiving the environment map. If the object becomes large in relation to the environment or the distance to the map center becomes larger, the geometric distortion increases. This is because the environment map is created as a projection from a single point in the center of the surface.

Geometric distortion can be reduced by tracking objects in the environment that are too close to the reflective object with a beam. If the reflective object is too complex, it may need to be tracked with ray tracing that Environmental Management cannot handle.

Techniques of environment mapping.

• The first usage technique of environment mapping was developed by Jim Blinn and Newell. In this case, the object is considered to be positioned in the middle of a large sphere, on the inside on which the environment is projected. The mapping used a latitude-longitude map indicated by the reflected beam, similar to the chrome mapping. The index function uses only the direction of R, resulting in errors in planar surfaces of large objects that tend to index to the same point on the map. Furthermore, the mapping is essentially a spherical projection and contains a singularity at (0, 0, Rz). In chrome mapping this led to peaks, while in this case distortions occur in the map around the singularities. This is a deterioration as it contributes to the final result. The difference between the longitude and latitude map and the chrome map is that in the first case the map is the surrounding area, while in the second case the map is any image. In the conversion both are identical.
• The other environmental technique is one in which the environment is projected onto the six sides of the cube. The environmental maps are created by taking six images from a fixed point in mutually orthogonal directions, either with a camera whose field of view is PI/2, or by creating the maps from a modeled scene with a renderer, which are then converted into six mip maps. The problem with using a real camera is that it is difficult to create a six-component map without encountering geometric and lighting discontinuities at the seams and boundaries. This technique is popular because it provides a clean way to combine computer generated objects and live action sets.

We hope that we were able to provide you with a first brief overview of environmental mapping. If you have any questions or suggestions, please feel free to contact our experts in our forum.

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