User Guide > Overview > Objects   

Creating a Light

You create lights at the object level using the Light tool. Press the tab key and start typing light then press Enter. Next, RMB-click to place the light which appears with its interactive handles ready. These handles let you position the light and set up parameters such as cone angle.

Editing the Light - Later when you want to edit the light using these handles, you can either select it using the Object tool which invokes the light handles or select it with the Transform tool which uses the transform handles then press enter to change to the light handles.

Topics covered:
Light Orientation handles
Light Types
Cone Angle Handles
Frustum Handles


Light Orientation Handles

The default light handle is the orientation handle. As you begin working with other handles, you can return to this handle by either RMB-clicking on the handle and selecting Orientation Handle, or pressing the o key. This handle lets you control the eye point and look-at point to position the light.

The orientation handle is made up of transform handles and rotation handles. The transform handles move either the look-at or eye point based on the light's local axes. This means that the handle will move perpendicular or tangential to the arc that runs between the two ends of the handle. The rotate handles let you move along the arc that runs between the two ends.If you click on either of the rotate handles then moving the opposite position handle will move both ends of the light setup instead of only the one end.

Tip: The light's look-at handle controls the rotation parameters on the light. If you want a separate look-at control then you will need to create a Null object and apply this to the light's Look-At attribute. This separate null object can be keyframed on its own or parented into another object hierarchy.


Light Types

When working with a light in Houdini, you can choose between a Point light and a Cone light. In Shading tab in the Parameter pane, scroll down to the no SHOP section and set Light Type.

A Point light sends light in all directions while the Cone light limits its illumination to a specific cone angle and direction.

Other Light Types

Area Light - Area Lights are available in Houdini as an extension of the two main light types. They set up an area where multiple point or cone lights are distributed.

Directional Light -You can create a Directional light by setting Projection to Orthographic in the Light parameters Viewing tab. This light type is similar to sunlight which casts parallel rays by the time it reaches earth.

Ambient Light - Ambient lights are available as a different object tool. Press the tab key and start typing ambient light then press Enter. Next, RMB-click to place the light.


Cone Angle Handles

To work with the Cone Angle handle, RMB-click on the handle and select Cone Handle, or press the z key. This handle lets you control the light's Far clipping planes and the light's Cone Angle and Cone Delta.


Frustum Handles

To work with the Cone Angle handle, RMB-click on the handle and select Frustum Handle, or press the f key. This handle lets you control the light's Near and Far clipping planes and the light's Frustum Aperture.

The light frustum is used when generating Depth Maps to determine the extent of the map. It is possible to set the frustum to a tighter angle if the Cone Angle is quite wide and you want sharper shadows. You can also RMB-click on the handle and select Link Cone and Frustum to make them work together.