Inserting
an Area or Linear Light Inserting
an Area or Linear Light An area or linear light can be created from an existing object or line. Unlike the other light source types, which are emitted from a specific, concentrated source, area and linear lights emanate from an extended object. This is useful for creating diffused light sources with softer lighting, such as fluorescent lights, neon lights, windows, and skylights.
An area light cannot be textured. Use a glow reflectivity shader to create textured objects that emit light only when indirect lighting is enabled in the Lighting Options dialog box.
The addition of multiple diffused light sources can add significantly to rendering time. For efficiency, replace a small area or line light with a point, spot, or directional light. In addition, since area lights can be slow to render, it may be better to use an Image Environment (HDRI) or physical sky background to supply the background (sky) lighting.
To create an area or linear light from an existing object or objects:
1. If creating an area light, select the object to convert to a light source; area light geometry should enclose a surface (a line or open polyline cannot be used, for example). Select a 2D line, closed 2D surface, or NURBS curve if creating a linear light.
Select more than one object to create several line or area lights at the same time.
Curved surfaces used for an area light require more rendering time than planar surfaces.
2. Select Modify > Convert > Convert to Area Light or Modify > Convert > Convert to Line Light.
The Light Preferences dialog box opens; indicate the area or line light parameters. Specify light intensity by entering a Get Brightness From value.
Click to show/hide the parameters.
3. Click Area Light Specs or Line Light Specs to set additional parameters.
The Area Light Data or Line Light Data dialog box opens.
Click to show/hide the parameters.
4. Click OK to return to the Light Preferences dialog box.
5. Click OK. The object or line is converted into a light. If more than one object was selected for conversion, the converted objects are grouped. The area light emits light in both surface directions.
The light must be rendered with a Renderworks product rendering mode. When an area light is on and rendered, it has constant reflectivity and does not receive shadows; when it is off, it displays as a normal object.
If a line light with Cast Shadows enabled is not casting light as expected, the center of the line light’s bounds may be inside another object, which prevents shadow calculations. If this occurs, either deselect Cast Shadows, use several line lights, or split the line light geometry into segments with their bounding centers located outside of another object.
The light parameters can be edited in the Object Info palette.
The area or linear light original geometry can be edited.
To edit the original light geometry:
1. Select the area or line light and then select Modify > Edit Light.
The Edit Light window opens, and the original 3D object or a NURBS representation of a 2D object is displayed.
2. The object geometry can be edited with the Reshape tool.
3. Click Exit Light at the top right of the drawing window to return to the drawing.
