You can render illumination and reflection from an infinite distance with High Dynamic range images. See Image-based lighting (sky-like illumination) and also Create blurry reflections using mental ray for Maya in the Shading guide.
How image-based lighting (IBL) works
When an IBL node is created one or more of the following mental ray for Maya shaders is used:
Along with Final Gathering this shader implements classic style image-based lighting. The color of the environment is picked up by final gather rays and incorporated into surface illumination. An environment shader is passive. It doesn’t actively contribute to the scene’s lighting; instead, it gets sampled only as needed. Best results are achieved if the IBL texture is diffuse. A specific case would be a texture consisting of a single color; this results in ambient occlusion computation.
A low-resolution control texture is computed (from the file or procedural IBL texture) and mapped to the IBL environment sphere. Whenever direct lights are sampled, the light shader is invoked. In this sense, the light shader approach is the most active one, and the most expensive. The IBL environment can be seen as one big area light. This approach works best (also due to importance sampling) if the IBL texture contains sharp features, and preferably contains many more black than non-black pixels.
These three approaches may be combined to achieve specific effects, at the expense of computation time.
The IBL manipulator tool appears in the scene view, and the IBL node’s Attribute Editor automatically pops up.
For details, see Image based lighting node attributes.
For details, see Position an IBL texture.
Final gathering picks up incandescence samples from the environment texture. Illumination models deal with these samples similar to direct light arriving from, for example, a spot light.
When you create an IBL node, its shape is represented in the scene view.
Moving (and to a certain extent scaling) the shape has no effect because the environment is considered infinitely distant. For best results, scale the shape as large as your clipping planes permit.
Rotations, however, let you position the texture on the IBL node shaders.