mia_envblur

Category: mental ray > Environment

Shader Family: Environment

Output: Color

Related Softimage shader: Environment Blur (mia)

The Environment Blur shader works by accepting some other environment shader as input, which would usually be a shader that performs an environment lookup in an HDRI environment map. This shader is intended to increase quality and performance of rendered objects that are largely reflecting the mental ray environment (that is, objects that do not primarily reflect other objects).

The Environment Blur shader is particularly useful in product visualization renderings that are surrounded by an HDRI environment map for reflections, and also for visual effects work where you want to integrate CG objects in a real world scene using HDRI reflections with smooth yet fast lookup.

The Environment Blur shader is not as useful for interior architectural renderings, since in those (enclosed) scenes, most reflection rays are bound to hit other objects and the purpose of this shader is to help reflection rays that do not hit other objects. Therefore, you will get the largest benefit in an "open" scene.

When the rendering starts, the Environment Blur shader performs a one-time setup and rasterizes the result of the environment shader into a special internal mipmap format. Then, as rendering proceeds, the shader can perform an extremely efficient blurring operation in the environment map in a way that provides a "look" very similar to shooting an extremely large number of glossy reflection rays, yielding a perfectly smooth result very quickly.

Name	The name of the shader node displayed in the render tree. Enter any name you like, or leave the default.
environment	Pick the actual environment shader looked up by this shader. If an environment is not specified, the global camera environment is used.
blur	The amount of blur (range 0.0 to 1.0) applied on the image. When set to 0.0, the internal mipmap is by-passed and the environment shader is looked up directly, as if the Environment Blur shader was not there.
mia_material_blur	When on, the blur amount is automatically calculated. Any reflective environment lookup performed by mia_material will cause the appropriate blur in mia_envblur (leave blur at 0.0 in this case).
resolution	The resolution of the internal pyramidal data structure used for the filtering. The default value of 200 means that a map of 200 x 200 samples are taken and stored, for subsequent filtering. This should be set high enough to resolve the smallest features in the environment map. A value of 200 is generally enough for any still image, but animations need higher resolutions such as 1000.