Houdini 22.0 Nodes Copernicus nodes

Light Copernicus node

Lights a layer given a light direction and normals.

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This node applies a simple lighting calculation for pixels based on the provided light direction, color, and normals.

Since lights are additive, you can create multiple lights with separate Light COPs and then add them together.

Parameters

Signature

The layer type that the source accepts.

See Signatures for more information.

Mask

The amount of the new value to mix in with the original value. Higher values mix in more of the new value. Lower values mix in less of the new value. You can also set the RGBA channels to which you apply the effects of this node.

The default value is 1, which means this node uses only the new value. See Mask for more information.

Toggle RGB

Turns the Red, Green, and Blue channels on and off.

Red

Applies this node’s effects to the Red channel.

Green

Applies this node’s effects to the Green channel.

Blue

Applies this node’s effects to the Blue channel.

Alpha

Applies this node’s effects to the Alpha channel.

Normal Type

The type of the input normal.

Signed (-1 to 1)

The input normal layer ranges from -1 to 1 and likely comes from geometry.

Offset (0 to 1)

The input nomral layer ranges from 0 to 1 and likely comes from a normal map.

See Normals for more information.

Light

Directional

Directional lights are considered at infinity. All the light rays will be parallel. When points are used as a source, the direction from the points to the origin is the direction of the light.

Non-directional lights are point lights emanating from the 3d location.

Light Direction

When no point geometry is provided, this is the direction pointing to the source light. The magnitude doesn’t matter.

The default value is 0, 0, 1.

Light Position

When no point geometry is provided, this is the center of the light when not directional.

Light Radius

Point lights have a singularity at their location, so if a point light is inside a volume it will become infinitely bright at that location. This regularizes the falloff by treating the light to be approximately a sphere of this radius.

This will be multiplied by the pscale attribute on points.

Light Color

The color of the light.

The default value is 1, 1, 1.

Intensity

The linear brightness of the light.

Exposure

An exponential brightness of the light. Each 1 value higher is 2 times the brightness.

Environment Map Offset

Angle to rotate the environment map around the Y-axis.

Material

Diffuse

A tint for the diffuse colour of the material. The incoming source layer will be multiplied by this to determine the diffuse contribution. Setting to zero can allow the extraction of the pure reflective or specular components.

Specular

A specular color for the material. This will be multiplied by the light color to form the specular color in light models that have specular, such as Phong.

Metallic

The amount of metallicity of the material. Increasing metallicity will lower the diffuse value and replace it with a reflected color.

Model

The lighting model to shade with.

Lambertian

An ideal matte surface.

Wrapped Diffuse

An extension of the Lambertian model, but allowing the specification of the terminator position. This allows the light to “wrap” around the surface and light the back half - this is useful for non-physical effects, especially for toon-shading pipelines where the light is further processed.

Phong

The Phong Reflection model, developed by Bui Tuong Phong, is a simple breakdown of light into a specular and diffuse component. The exponent controls how sharp the specular effect is.

Terminator

Where the terminator of the Wrapped Diffuse should lie. -1 will make it entirely black, 0 will be at the half way part and so match Lambertian shading, and 1 will wrap all the way to the far side of the object.

Exponent

The tightness of the specular lobe in the Phong model.

Inputs

source

A layer to perform lighting on.

normal

An RGB layer providing the surface normal. Its normal type, offset or signed, must match the normal type of this node.

pos

Instead of using the location of the source pixel in world space; this RGB input’s value is used.

metallic

A scale multiplier to the metallic value, the metallic parameter likely should be set to 1 for this to have an effect

vieworigin

Instead of using the source input, this layer provides a ray direction for each output pixel. This is required for Phong and metallic shading.

points

An optional Geometry whose points will be treated as light sources. For positional lights their positions are used, otherwise their direction to the origin is used as a direction.

When wired the corresponding direction or position parameters will be unused.

envmap

An optional RGB layer storing the environment map in polar coordinates.

mask

An optional per-pixel mask amount that’s scaled by the Mask parameter.

Outputs

lit

The final lit layer.

See also

Copernicus nodes