To add any lights to a scene an Arnold Light node needs to be created. This node is used for all lights in Arnold for Houdini. It can be used as a point, distant, spot, disk, cylinder, quad, meshskydome or photometric.

 

 

An Arnold Light node can be created by tab-typing Arnold Light in the Network Editor at object level (Tab > Arnold > Arnold Light).

The native Houdini lights won't be translated. Arnold lights must be used.

Common Parameters

These properties are available to all types of Arnold Lights.

Light Type

Controls the shape of the light source. Options are pointdistantspotdisccylinderquadmesh or skydome.

Enable Light

Sets whether a light contributed to the illumination of the current scene.

Although the light will not contribute in the render, it will still be visible in the viewport.

Color Type

Choose between Simple Color, Texture or Shader.

Color

Controls the color of the emitted light.

Intensity

Exposure

Samples

Volume Samples

'Volume Samples' does not apply to the 'Volume Scattering' atmosphere shader in the Environment section. To improve the quality of the 'Volume Scattering' atmosphere shader, you must increase the 'Atmospheric Scattering' samples.

The half distance attenuation that is available on Houdini lights is not supported in Arnold. To tweak the attenuation use the Light Decay filter.

Normalize


Shadows

These settings are common to all lights.

Shadow Color

Shadow Density

Cast Shadows

Cast Atmospheric Shadows


Filters

Arnold light filters are arbitrary shaders that can modify a light's output based on distance, position or other factors. This makes it easy to extend the built-in light sources with additional effects.

 

Light Filters are created within Arnold Shader Networks and must be connected to a light filter output node. You can connect several filters. The vopnet is then connected to Arnold Lights under the Light Filter tab. For convenience, a default shader network containing a light filter output for is created within the light node.

More information can be found in the Light Filters section.

 


Contribution

 These settings are common to all lights. Indirect was previously Bounce Factor.

Indirect

Max Bounces

AOV Light Group

Information about creating per-light AOVs can be found here.


Viewport

Turns on/off the preview of the effect of the light in the Houdini viewport.

Although the light will not be visible in the viewport, it will still contribute to the render.

 


Specific Light Parameters

See the pages below for more information on specific light types.