Reflection

 

The Standard shader has a secondary layer of reflection, called simply reflection, which is perfectly sharp and mirror-like. It should only be used to replicate perfect mirrors or glass shaders. If you want blurry reflections only you should use Specular.

Color

The color of the reflection ray at the current point. 

Reflection Color 0-1


The contribution from reflection rays (the amount of light that the surface reflects).

Reflection 0-1

 

You will notice in the image below, that the light source is not visible in the reflection. This is because reflectivity does not sample light sources (direct light). Therefore, it is recommended that you use Specularity with glossy materials, unless a pure 'mirror' reflection is required.

In the chrome sphere below you can see the difference between the Specular and Reflection attributes when using a SkyDome light. Notice the difference between the Specular and Reflective highlights of the window in the chrome sphere and wood surface.

Enable internal reflections

Unchecking internal reflections will disable indirect specular and mirror perfect reflection computations when ray refraction depth is bigger than zero (when there has been at least one refraction ray traced in the current ray tree).

In the right image below, the sphere appears black because Enable Internal Reflections is disabled in the Standard shader assigned to the sphere.

Disabling 'Enable Internal Reflections' can dramatically reduced render times for highly reflective/ refractive scenes.

Fresnel (Enable)

Enables or disables the Fresnel effect.

Reflectance At Normal

The Fresnel effect is more noticeable when using lower values. Increasing this value gives the material a more metallic-like specular reflection. Metals have a more uniform reflectance across all angles compared to plastics or dielectrics, which have very little normal reflectance. Note that the Fresnel effect is less evident when a surface becomes rougher (the unpredictable nature of a rough surface 'scatters' the Fresnel effect, preventing the viewer from being able to clearly see it). As visible in the images below, objects rendered with a correct Fresnel effect will appear to have brighter specular reflections near the edges. 

All types of materials tend to have full reflectivity at grazing angles, as evident in the diagram below:

 

The examples below show various materials which require Reflectance at Normal:

For realistic materials, reflectance at normal must be lower than the specular/reflection scale (which controls the reflectance at grazing). Otherwise, you will get a darker reflection at the edges, which is exactly the opposite of the effect seen in nature. It is also not advisable to tint speculars when using Fresnel as this is not physically correct.


Note that it is also possible to map a texture to Reflectance at Normal in order to control the intensity of the Fresnel effect:


V ramp texture connected to 'Reflectance at Normal' (1 to 0). Rollover image.

Reflection Exit Color

The color returned when a ray has reached its maximum reflection depth value. 


 

 

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