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.

The color of area lights can be filtered by a texture, texture color, or the fill color of the original geometry. This feature can be used to create a wide variety of lighting effects, including skylights and stained glass windows.

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.

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 loading a distribution file or by manually entering a Get Brightness From value.

 

Parameter	Description
On/Off	Shows or hides the light produced by the light source
Color	Specifies a color associated with the light source; click the color box to select the color. This parameter is not available if a Color Temperature is specified.
Cast Shadows	Creates shadows
Dimmer	Dims the light source brightness (intensity); enter a percentage or drag the slider bar. Only the brightness of the light source is affected; the color temperature is not changed.
Use Emitter	An area or line light’s actual brightness and color temperature must be specified, so this setting is not optional
Get Brightness From	Specifies the luminous quantity of the area or line light as a manually entered value or from a loaded distribution file
User Input	Manually specifies the luminous quantity of an area light as an accurate number; the units of a line light are always Lumens
Distribution File	Sets intensity distribution data with a standard file specified in Area Light Specs or Line Light Specs. The brightness value is obtained using the integral of the raw emission data provided with the file.
Color Temperature	Specifies the light color temperature in Kelvin. This refers to an ideal black body emitter, glowing “red hot” or “white hot.” A lower temperature generates an orange color; the hotter the temperature, the closer to white the color of the light is (see Correlated Color Temperature for typical light source color temperature ranges). Specifying this parameter is optional. If not specified, the default temperature is 0, meaning that the final emission color for the light is entirely controlled by the selection in Color. When the temperature is specified, Color cannot be changed. The final emission color is set by the Color Temperature. Color temperature settings can be white-balanced on a per-layer basis; see Setting Lighting Options.
Area or Line Light Specs	Sets specific area or line light options and loads a distribution file

3.	Click Area Light Specs or Line Light Specs to set additional parameters or load a distribution file.

The Area Light Data or Line Light Data dialog box opens.

 

Parameter	Description
Dist Falloff	Select the distance falloff function (rate of intensity change while moving along the beam away from the light source)
Quality	Specifies the sampling quality of the light; select From Render Mode to use the setting specified in Area/Line Light Quality in the rendering options
Color Filtering (area light only)	Filters the color of the light emanating from the area light object by the fill color or texture of its original geometry
Render Geometry	Renders the light object geometry; deselect to hide the original geometry when rendering
Use Distribution File	Specifies whether to use the attached emission profile data file for the light intensity information
Distribution File	Displays the distribution file name when a valid distribution file has been selected, or “None” if a valid distribution file has not been designated (click Load Distribution to specify a file)
Load Distribution	Loads light emission profile data from a standard file. The brightness value is obtained using the integral of the raw emission data provided with the file. The file must be a text file with industry standard intensity distribution data in CIE, IESNA, CIBSE, or EULUMADAT format (.ies, .cib, .cie, and .ldt).

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 different directions of the light being emitted by an area light are indicated by arrows drawn on every surface.

Deselect Show Direction in the Object Info palette of a selected area light to hide the light direction indicators.

The light must be rendered with a RenderWorks 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.

Editing an Area or Linear Light

The light parameters can be edited in the Object Info palette; see Light Source Properties.

An area light can be textured to create a variety of effects. From the Render tab of the Object Info palette, select a texture from either the default resources or the current file’s resources (see VectorWorks Fundamentals Default Resources). The color of the emitted light can be filtered by the texture color(s) or by the color of the original geometry, when Color Filtering is selected 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 Group 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 2D Reshape or 3D Reshape tool. In addition, the fill color of the original object can be changed to modify the color filtering properties of an area light.

3.	Click Exit Light at the top right of the drawing window to return to the drawing.