Adding Light Sources

The Light tool places light sources in the drawing. Select the type of light and specify the light preferences from the Tool bar.

Mode	Description
Directional Light	Projects light with parallel rays, like the sun
Point Light	Radiates light in all directions, like a bare light bulb
Spot Light	Projects light in a specific direction, aimed at a specific object, like a flashlight or conventional spotlight
Default Direction	For directional lights, click to specify the light position
Set Direction	For directional lights, click to set the light direction, and then click to specify the light position
Light Preferences	Sets the preferred light parameters

Mode

Description

Directional Light

Projects light with parallel rays, like the sun

Point Light

Radiates light in all directions, like a bare light bulb

Spot Light

Projects light in a specific direction, aimed at a specific object, like a flashlight or conventional spotlight

Default Direction

For directional lights, click to specify the light position

Set Direction

For directional lights, click to set the light direction, and then click to specify the light position

Light Preferences

Sets the preferred light parameters

	To add a light source:

From the Tool bar, select the type of light source to insert (directional light, point light, or spot light). If inserting a directional light, select the light placement method (Default Direction or Set Direction).

2.	Click the Light Preferences Tool bar button to specify the light source preferences for this session. Depending on the light source selected, different parameters are available. In addition, certain parameters are only available when RenderWorks is installed.

The Light Preferences dialog box opens.

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 Use Emitter is selected and a Color Temperature is specified (RenderWorks required).
Cast Shadows (RenderWorks required)	Select to create shadows
Brightness	Specifies the light source brightness; enter a percentage or drag the slider bar. A value over 100% can be entered. This parameter is not available if Use Emitter is selected (RenderWorks required).
Use Emitter (RenderWorks required)	For accuracy, specifies the light’s actual brightness and color temperature; leave deselected to use the light as a simple light source
Get Brightness From (RenderWorks required)	Specifies the luminous quantity of a light
User Input (RenderWorks required)	Specifies the brightness as an accurate number in Lux, Lumens, Footcandles, or Candelas; the units vary depending on the light source
Distribution File (RenderWorks required)	Does not apply to directional, point, or spot lights (see Advanced RenderWorks Lighting)
Color Temperature (RenderWorks required)	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. 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.
Directional, Spot, or Point Light Specs	Click to set additional specifications for the light source

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 Use Emitter is selected and a Color Temperature is specified (RenderWorks required).

Cast Shadows
(RenderWorks required)

Select to create shadows

Brightness

Specifies the light source brightness; enter a percentage or drag the slider bar. A value over 100% can be entered. This parameter is not available if Use Emitter is selected (RenderWorks required).

Use Emitter
(RenderWorks required)

For accuracy, specifies the light’s actual brightness and color temperature; leave deselected to use the light as a simple light source

Get Brightness From
(RenderWorks required)

Specifies the luminous quantity of a light

User Input
(RenderWorks required)

Specifies the brightness as an accurate number in Lux, Lumens, Footcandles, or Candelas; the units vary depending on the light source

Distribution File
(RenderWorks required)

Does not apply to directional, point, or spot lights (see Advanced RenderWorks Lighting)

Color Temperature
(RenderWorks required)

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.

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.

Directional, Spot, or Point Light Specs

Click to set additional specifications for the light source

3.	Click Directional Light Specs, Spot Light Specs, or Point Light Specs, for the selected light source type, to specify additional parameters.

Parameter	Description
Directional Light
Direction	Specifies the light’s direction by either specifying the light angle or vector
Angle	Sets the light’s angle by azimuth and elevation. The azimuth angle is set based on an angle of 0 degrees at the negative Y axis, and is positive in a counter-clockwise direction; the elevation angle is the angle above (positive) or below (negative) the horizon.
Vector	Indicates the direction of the light by specifying the coordinates of its X, Y, and Z delta vectors
Point Light
Dist Falloff	Select the distance falloff function (rate of intensity change while moving along the beam away from the light source)
Spot Lights
Spread/Beam diagram	Drag the handles on the diagram to set the spot light Spread and Beam angles, or enter the values in the fields below the diagram
Spread	Specifies the spread angle of the spot light (light cone’s maximum angle)
Beam	Specifies the beam angle of the spot light (cone of light that does not change intensity up to the spread angle, after which the angle falloff determines its intensity)
Falloffs	Specify the distance and angle falloff function
Dist Falloff	Select the distance falloff function (rate of intensity change while moving along the beam away from the light source)
Ang Falloff	Select the angle falloff function (specifies the rate of intensity change between the beam and the spread)

Specifies the light’s direction by either specifying the light angle or vector

Angle

Sets the light’s angle by azimuth and elevation. The azimuth angle is set based on an angle of 0 degrees at the negative Y axis, and is positive in a counter-clockwise direction; the elevation angle is the angle above (positive) or below (negative) the horizon.

Vector

Indicates the direction of the light by specifying the coordinates of its X, Y, and Z delta vectors

Point Light

Dist Falloff

Select the distance falloff function (rate of intensity change while moving along the beam away from the light source)

Spot Lights

Spread/Beam diagram

Drag the handles on the diagram to set the spot light Spread and Beam angles, or enter the values in the fields below the diagram

Spread

Specifies the spread angle of the spot light (light cone’s maximum angle)

Beam

Specifies the beam angle of the spot light (cone of light that does not change intensity up to the spread angle, after which the angle falloff determines its intensity)

Falloffs

Specify the distance and angle falloff function

Dist Falloff

Select the distance falloff function (rate of intensity change while moving along the beam away from the light source)

Ang Falloff

Select the angle falloff function (specifies the rate of intensity change between the beam and the spread)

4.	Click OK to return to the Light Preferences dialog box. Click OK to return to the drawing.

If placing a directional light, click to specify the light position in Default Direction mode. In Set Direction mode, click once to specify the light target or direction, and then click a second time to specify the light position.

If placing a spot light, click to place the light, and then drag to specify the light direction and target. The spot light can be aimed at any object. Click again to set the spot light. The target Z height can be adjusted precisely with the Look To Height parameter of the Object Info palette.

The spot light target handle and projection line only display when the spot light is selected. Use the 2D/3D Selection tools to move the light. The target handle aims the spot light and can be adjusted with the 3D Selection tool once the spot light has been created. Use the 3D Reshape tool to move the target handle constrained about an axis selected in the Tool bar.

Parameter	Description
Kind	Indicates the type of light source; change to a different type by selecting a different kind from the displayed list A custom, area, or line light requires RenderWorks.
On/Off	Shows or hides the light produced by the light source; this setting can also be accessed from the light context menu
Auto Update	Automatically renders the drawing when rendering-related parameters change
Update	When Auto Update is deselected, click to render the drawing when rendering-related parameters change
Cast Shadows (RenderWorks required)	Select to create shadows
Lit Fog (RenderWorks required)	Creates a special volumetric lighting effect for the light source when used in combination with the Lit Fog RenderWorks background weather effect (see Creating Weather Effects)
Use Emitter (RenderWorks required)	For accuracy, specifies the light’s actual brightness and color temperature; leave deselected to use the light as a simple light source. Required for a custom, area, or line light.
Brightness	Specifies the light source brightness; enter a percentage or drag the slider bar. A value over 100% can be entered. This parameter is not available for custom, area, and line lights, or if Use Emitter is selected (RenderWorks required).
Brightness From (RenderWorks required)	Specifies the location of the light intensity data for a custom, line, or area light (either user input or distribution file); the distribution file can be specified by clicking Load Distribution
Brightness Value (RenderWorks required)	Specifies the brightness as an accurate number
Brightness Unit (RenderWorks required)	Select Lux, Lumens, Footcandles, or Candelas for the unit of Brightness; the available units depend on the light type
Dimmer (RenderWorks required)	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.
Light Rotation Angle (RenderWorks required)	Specifies the rotation angle of a custom light source around an axis connecting the light location to the light target; this angle defines the plane for the intensity distribution curve, and is displayed in red on the custom light object
Use Distribution File (RenderWorks required)	Specifies whether to use the attached emission profile data file for the area or line light intensity information; distribution data is required for a custom light
Distribution File (RenderWorks required)	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 (RenderWorks required)	For a custom, area, or line light, 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).
Color Temperature (RenderWorks required)	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.
Color	Specifies a color associated with the light source; click the color box to select the color. This parameter is not available if Use Emitter is selected and a Color Temperature is specified (RenderWorks required).
Color Filtering (RenderWorks required)	For area lights, filters the color of the light emanating from the area light object by the color or texture of its original geometry
Dist Fall	Indicates the distance falloff function for a point, spot, custom, area, or line light (specifies the rate of intensity change while moving along the beam away from the light source)
Quality (RenderWorks required)	For area and line lights, 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
Render Geometry (RenderWorks required)	For area and line lights, renders the light object geometry
Show Direction (RenderWorks required)	For area lights, shows the light direction indicators
Flip Direction (RenderWorks required)	For area lights, flips the direction of the light being emitted
Ang Fall	Select the angle falloff function (rate of intensity change between the beam and the spread)
Spread/Beam diagram	Drag the handles on the diagram to set the spot light Spread and Beam angles, or enter the values in the fields below the diagram
Spread	Specifies the spread angle of the spot light (light cone’s maximum angle)
Beam	Specifies the beam angle of the spot light (cone of light that does not change intensity up to the spread angle, after which the angle falloff determines its intensity)
X/Y/Z or I/J/K	Specifies the location of the light source in relation to the ground plane or working plane
Look To Height	For spot lights, sets the Z height above the ground plane of the spot light target handle
Azimuth	Indicates the azimuth for a directional light (South at zero degrees); enter new values or drag the slider bar to set
Elevation	Indicates the elevation (degrees above the horizon) for a directional light; enter new values or drag the slider bar to set
Pan/Tilt	Click the top button to display the spot light or custom light beam pan and tilt angles; enter new values or drag the slider bar to set
±X/±Y/±Z	Click the bottom button to display the light beam direction in terms of its X, Y, and Z components
Set Light to View	Sets the orientation of the directional, spot, or custom light to that of the current view; this function can also be accessed from the light context menu
Set View to Light	Sets the orientation of the current view to that of the directional, spot, or custom light; this function can also be accessed from the light context menu

Parameter

Description

Kind

Indicates the type of light source; change to a different type by selecting a different kind from the displayed list

A custom, area, or line light requires RenderWorks.

On/Off

Shows or hides the light produced by the light source; this setting can also be accessed from the light context menu

Auto Update

Automatically renders the drawing when rendering-related parameters change

Update

When Auto Update is deselected, click to render the drawing when rendering-related parameters change

Cast Shadows
(RenderWorks required)

Select to create shadows

Lit Fog
(RenderWorks required)

Creates a special volumetric lighting effect for the light source when used in combination with the Lit Fog RenderWorks background weather effect (see Creating Weather Effects)

Use Emitter
(RenderWorks required)

For accuracy, specifies the light’s actual brightness and color temperature; leave deselected to use the light as a simple light source. Required for a custom, area, or line light.

Brightness

Specifies the light source brightness; enter a percentage or drag the slider bar. A value over 100% can be entered. This parameter is not available for custom, area, and line lights, or if Use Emitter is selected (RenderWorks required).

Brightness From
(RenderWorks required)

Specifies the location of the light intensity data for a custom, line, or area light (either user input or distribution file); the distribution file can be specified by clicking Load Distribution

Brightness Value
(RenderWorks required)

Specifies the brightness as an accurate number

Brightness Unit
(RenderWorks required)

Select Lux, Lumens, Footcandles, or Candelas for the unit of Brightness; the available units depend on the light type

Dimmer
(RenderWorks required)

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.

Light Rotation Angle
(RenderWorks required)

Specifies the rotation angle of a custom light source around an axis connecting the light location to the light target; this angle defines the plane for the intensity distribution curve, and is displayed in red on the custom light object

Use Distribution File
(RenderWorks required)

Specifies whether to use the attached emission profile data file for the area or line light intensity information; distribution data is required for a custom light

Distribution File
(RenderWorks required)

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
(RenderWorks required)

For a custom, area, or line light, 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).

Color Temperature
(RenderWorks required)

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.

Color

Color Filtering
(RenderWorks required)

For area lights, filters the color of the light emanating from the area light object by the color or texture of its original geometry

Dist Fall

Indicates the distance falloff function for a point, spot, custom, area, or line light (specifies the rate of intensity change while moving along the beam away from the light source)

Quality
(RenderWorks required)

For area and line lights, 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

Render Geometry
(RenderWorks required)

For area and line lights, renders the light object geometry

Show Direction
(RenderWorks required)

For area lights, shows the light direction indicators

Flip Direction
(RenderWorks required)

For area lights, flips the direction of the light being emitted

Ang Fall

Select the angle falloff function (rate of intensity change between the beam and the spread)

Spread/Beam diagram

Drag the handles on the diagram to set the spot light Spread and Beam angles, or enter the values in the fields below the diagram

Spread

Specifies the spread angle of the spot light (light cone’s maximum angle)

Beam

Specifies the beam angle of the spot light (cone of light that does not change intensity up to the spread angle, after which the angle falloff determines its intensity)

X/Y/Z or I/J/K

Specifies the location of the light source in relation to the ground plane or working plane

Look To Height

For spot lights, sets the Z height above the ground plane of the spot light target handle

Azimuth

Indicates the azimuth for a directional light (South at zero degrees); enter new values or drag the slider bar to set

Elevation

Indicates the elevation (degrees above the horizon) for a directional light; enter new values or drag the slider bar to set

Pan/Tilt

Click the top button to display the spot light or custom light beam pan and tilt angles; enter new values or drag the slider bar to set

±X/±Y/±Z

Click the bottom button to display the light beam direction in terms of its X, Y, and Z components

Set Light to View

Sets the orientation of the directional, spot, or custom light to that of the current view; this function can also be accessed from the light context menu

Set View to Light

Sets the orientation of the current view to that of the directional, spot, or custom light; this function can also be accessed from the light context menu

Once a light has been placed on the drawing, the 2D Selection or 3D Selection tool can be used to change its location, and, depending on the light type, beam parameters.

Light Type	Beam Parameter	Description
Point, Spot, Directional	Light location	Click on the light with the move cursor and drag it to its new location The spot light target handle is not locked to its target. The target handle location may need re-adjusting after moving the spot light.
Spot, Directional	Orientation and view	Select the light; in the Object Info palette, click Set Light to View to set the light orientation to the current view orientation, or click Set View to Light to set the orientation of the view to that of the light
Directional	Azimuth and elevation direction	Click on the azimuth or elevation control points to change the directional light parameters. Move the handles with the mouse, or enter the azimuth and elevation values in the Data bar.
Spot	Target direction	Click on the handle with the 3D Selection tool to change the spot light target direction; drag to the new target and click to set
Directional	Beam direction	Click and drag with the hand cursor to change the beam direction

Light Type

Beam Parameter

Description

Point, Spot, Directional

Light location

Click on the light with the move cursor and drag it to its new location

The spot light target handle is not locked to its target. The target handle location may need re-adjusting after moving the spot light.

Spot, Directional

Orientation and view

Select the light; in the Object Info palette, click Set Light to View to set the light orientation to the current view orientation, or click Set View to Light to set the orientation of the view to that of the light

Directional

Azimuth and elevation direction

Click on the azimuth or elevation control points to change the directional light parameters. Move the handles with the mouse, or enter the azimuth and elevation values in the Data bar.

Spot

Target direction

Click on the handle with the 3D Selection tool to change the spot light target direction; drag to the new target and click to set

Directional

Beam direction

Click and drag with the hand cursor to change the beam direction