About creating a Cube environment
- To use a cube texture to simulate reflections from a real-world or CG environment, from the center of the environment in all six directions either take photographs of (real-world) or render (CG) the environment. Then map a cube texture to a shader’s Reflection parameter, and assign the six images to the cube texture. Scale and position the texture placement object so that it corresponds to the dimensions of the original environment. Assign the shader to an object in your scene and render (raycast). The object appears to reflect the original environment accurately.
- In order to use a cube texture to map six image files onto the inner surface of an infinite cube, set the ALIAS_INFINITE_CUBE environment variable.
- Use Bluroffset to unfocus reflections when using the cube environment texture as a reflection map to simulate unpolished surfaces.
- The advantage to Cube environment maps is that they can be blurred as much as you want without any additional computing cost. When you generate a background from an environment map, the amount of blurring required to prevent aliasing increases with the field of view. In practice, very little blurring results when you use images with a 5122 texture and a field of view less than 90×.
- For reflection mapped surfaces however, the amount of blurring depends on the surface curvature and the distance from the eye point. This cannot be computed automatically. Using the Blur_offset slider in the Blur window lets you unfocus the reflections by a desired amount (see Common Surface Texture Parameters for more information). In fact, soft-focus reflections can be used to simulate less than perfectly polished surfaces.
- The reflections on a surface mapped with an infinite cube texture do not change when you scale or move the surface or the texture placement object. The reflections on a surface mapped with a finite cube do change when you scale or move the surface or the texture placement object.