Refract from Height Copernicus node

Refracts an image through a height layer.

On this page	Parameters Height Ground Color Reflection Inputs Outputs
Since	22.0

This node treats the height input as the surface of a transparent medium and the source image as a layer on the ground below it. It traces view rays through the surface, refracts them using the surface normal, and samples the source image at the refracted ground position.

You can use this to create images seen through water, glass, thin ice, or another transparent surface. The node can also add Fresnel-style reflection from an environment map. If the source has alpha and an environment map is wired, transparent parts of the source reveal the refracted environment behind it.

Parameters ¶

Signature

The layer type that the source accepts.

See Signatures for more information.

Filter

The method used to sample the source image.

The default value is Box. See Filters for more information.

Space

Local

Use the source layer’s local space for the view direction or position.

World

Use world space for the view direction or position.

Normal Type

The format of the normal input. This is available when the normal input is wired.

See Normals for more information.

Signed (-1 to 1)

Treat the normal input as signed normals, compatible with geometry attributes.

Offset (0 to 1)

Treat the normal input as offset normals, compatible with normal maps.

Directional

Use a directional view ray. When this is off, the node uses a point view position.

View Azimuth

The horizontal angle of the directional view ray.

View Altitude

The vertical angle of the directional view ray above the horizon.

View Position

The point view position in the selected space.

Height ¶

Index of Refraction

The index of refraction of the transparent medium. The default value of 1.33 approximates water.

Height Offset

The value to add to the height layer before tracing rays. If the normal input is wired without a height input, this sets the flat surface height.

Height Scale

The value to multiply the height layer by before tracing rays. This is disabled when a normal input is wired.

Compute Derivative outside Image

Allows the internal derivative calculation for the height surface to read outside the image bounds. This affects the surface normals used for refraction.

Kernel Size

The kernel size for the internal derivative calculation on the height surface.

Ground ¶

Ground parameters are available when a ground height layer is wired.

Index of Refraction

The index of refraction of the medium below the ground surface. The default value of 1.0 approximates air.

Ground Offset

The value to add to the ground height before tracing ray intersections.

Ground Scale

The value to multiply the ground height by before tracing ray intersections.

Ray Trace Iterations

The number of Newton iterations used to approximate where refracted view rays intersect the ground height layer.

Compute Derivative outside Image

Allows the internal derivative calculation for the ground layer to read outside the image bounds. This affects the ray-ground intersection solve.

Kernel Size

The kernel size for the internal derivative calculation on the ground layer.

Color ¶

Material

The transparent material used for spectral dispersion and absorbance. Use a higher Number of Colors value for smoother dispersion.

Water

Uses water-like dispersion and absorbance.

Glass

Uses glass-like dispersion and absorbance.

Diamond

Uses diamond-like dispersion and uniform absorbance in the entire wavelengths.

Medium Color

The tint color of the transparent medium.

Light Absorbance

Controls how much light is absorbed as rays travel through the medium. Higher values make deeper or longer paths darker and more affected by the medium’s material and color.

Dispersion

The amount of spectral dispersion. Higher values increase color separation.

Number of Colors

The number of wavelength samples used for dispersion. Higher values create smoother dispersion, but take longer to cook.

Reflection ¶

Strength

The strength of the reflected environment.

Bias

Controls the distribution of the reflection. Lower values spread the reflection more broadly across the surface, while higher values concentrate it near stronger Fresnel highlights.

Color

The tint color of the reflection.

Saturation Scale

Multiplies the saturation of the reflected environment.

Environment Map Offset

Rotates the environment map projection used for reflection and refracted background lookup.

Inputs ¶

source

The Mono, UV, RGB, or RGBA layer to sample through the refractive surface.

height

The height layer representing the surface of the transparent medium. If the normal input is wired, the node uses the normal input for surface normals instead of computing them from height derivatives.

ground

An optional height layer representing the ground surface where the source image is sampled.

normal

An optional RGB layer that stores the surface normals in either Signed or Offset format.

envmap

An optional environment map used for surface reflection and for the refracted background behind transparent source pixels.

Outputs ¶

result

The final RGB image with refraction and reflection.

refract

The RGB image containing the refracted source image.

reflect

The RGB image containing the reflected environment.