Houdini 20.5 Mantra rendering

Light bank

The light bank is a data tree view that lets you set various parameters on all lights in a scene through a single interface.

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Overview

Each light in the scene is represented by a row in the spreadsheet. The columns in the spreadsheet let you rename lights, turn them on or off, link lights to objects, and change commonly used parameters such as light intensity.

How to

To...Do this

Create a light bank pane

  1. Click the New tab icon in the top line of a pane.

  2. Choose New pane tab type ▸ Data tree.

  3. Click the pop-up menu in the top left corner and choose “Light bank”.

Turn a single light on and all other lights off (solo)

Click the Solo radio button for the light in the spreadsheet.

Click the radio button again to turn off soloing.

Turn a single light off (mute)

Click the Mute checkbox for the light in the spreadsheet.

Turn the checkbox off to re-enable the light.

  1. In the spreadsheet, click the “Link” cell for the light.

  2. Click the icon to select the objects from a chooser, or if you know the paths of the objects you want to link, you can edit the cell contents directly.

Editing this cell automatically sets the Light mask on the linked objects. You can use a name pattern (for example hero*).

Change light intensity, color, type, or category tags

In the spreadsheet, click in a cell to edit the value. This changes the corresponding parameter on the light object.

Tips

  • Net boxes and sub-networks appear as levels of hierarchy in the spreadsheet tree. You can use them to organize both the network and the light bank.

  • For object-centric editing of light tags, use the appearance editor.

Showing custom lights in the light bank

If you create a custom light asset, you need to do a little bit of extra work to have the light bank recognize instances of the asset as lights.

  1. Open the type properties for the asset: right click the asset and choose Type properties. (If the asset is locked, you first need to right click the asset and choose Allow editing of contents.)

  2. In the Extra files tab, click Add empty section and change the Section name to LightBank.

  3. On the right side, you can write JSON to configure how to map the light bank interface to parameters on your light asset.

The JSON can have three keys:

enable

A parameter name string specifying the name of the parameter that controls whether your asset emits light. The light bank changes this parameter when you use its “solo” or “mute” controls.

color

A string specifying the name of the parameter that controls your asset’s color. The light bank maps this to a color control in the spreadsheet.

extra

A list (array) of strings specifying the names of parameters to include as extra columns in the light spreadsheet. Houdini will automatically provide an editing UI for the parameter values based on the parameter type.

For example:

{
    "enable": "tl_enable",
    "color": "tl_color",
    "extra" : ["tl_intensity", "tl_teatime"]
}

Mantra rendering

Mantra user guide

Basics

Lighting

Next steps

Guru-level

Other renderers