IES Sun Light (Photometric)

Create Panel > Systems > Create a Daylight system in your scene. > Modify Panel > Daylight Parameters Rollout > Sunlight > Choose IES Sun.

Create panel > Lights > Photometric > IES Sun

Create menu > Lights > IES Sun

Outdoor scene illuminated by the IES Sun light

IES Sun is a physically-based light object that simulates sunlight. When used in conjunction with a daylight system, its values are set automatically based on geographic location, time, and date.

Note: While you can create daylight lights manually, you should use them in conjunction with the Daylight system to get the best results. The Daylight system combines the two daylight components of sun and sky in a unified interface.

Tip: If you use the IES sun or sky with the Logarithmic Exposure Control, check both the Daylight and Exterior option. This will provide greater control for properly mapping the higher energy levels to RGB colors.

Tip: In addition, it is important to set the Physical Scale to the brightest light source in your scene. If the IES Sun is used, set the Physical Scale to 90000 cd.

Note: When you add an IES Sun light, the software automatically assigns a Look At controller to it, with the the light's target object assigned as the Look At target. You can use the controller settings on the Motion panel to assign any other object in the scene as the Look At target.

Interface

Sun Parameters rollout

On—Turns the sunlight on and off in the viewport.

Targeted—When on, the IES Sun is targeted to the center of the compass rose created by the Daylight system. If this is off, the position of the sun can be set manually.

Intensity—The intensity of the sunlight. The color swatch to the right of the spinner opens the Color Selector to set the color of the light. Typical intensities in a clear sky are around 90,000 lux.

Note: Intensity is set automatically and cannot be set manually if the sun is under the control of a daylight system.

Shadows group

On—Determines whether the sunlight casts shadows or not.

Shadow Method drop-down list—Determines whether the renderer uses shadow maps, ray-traced shadows, advanced ray-traced shadows, or area shadows to generate shadows for this light.

Each shadow type has a rollout with its associated controls.

Use Global Settings—Turn on to use global settings for shadows cast by this light. Turn off to enable individual control of the shadows. If you choose not to use the global settings, you must choose which method the renderer will use to generate shadows for this particular light.

When Use Global Settings is on, the shadow parameters switch over to show you what the current global setting is. This data is shared by every other light of this class. When Use Global Settings is off, the shadow parameters are specific to that particular light.

Exclude—Excludes selected objects from the effects of the light. Click this button to display the Exclude/Include dialog.

Excluded objects still appear lit in shaded viewports. Exclusion takes effect only when you render the scene.

Shadow Parameters rollout

This rollout is similar to the Shadow Parameters rollout for standard and photometric lights, except you cannot set a shadow map or shadow color.

Advanced Effects rollout

Contrast—Adjusts the contrast between the diffuse and ambient areas of the surface. Leave this set to 0 for normal contrast. Increase the value to increase the contrast for special effects: for example, the harsh light of outer space. Default=0.0.

Soften Diffuse Edge—Increasing the value of Soften Diffuse Edge softens the edge between the diffuse and ambient portions of a surface. This helps eliminate edges that can appear on a surface under certain circumstances. Default=50.

Note: Soften Diffuse Edge slightly reduces the intensity of the light. You can counter this, to some extent, by increasing the Multiplier value.

Diffuse—When on, the light affects the diffuse properties of an object's surface. When off, the light has no effect on the diffuse surface. Default=on.

Specular—When on, the light affects the specular properties of an object's surface. When off, the light has no effect on the specular properties. Default=on.

For example, by using the Diffuse and Specular check boxes you can have one light color the specular highlights of an object, while not coloring its diffuse component, and then have a second light color the diffuse component of the surface while not creating specular highlights.

Optimizations rollout

This rollout is identical to the Optimizations rollout for advanced ray-traced and area shadows.


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