Topics Covered:

Class 7: Let There Be Light


This class is all about adding light features to a prim to make it shine and dazzle in its environment.

Lots of Lights

Note: This class will not be covering the topic of light effects via a Light Switch script. This topic will be covered in a later class when we look at using scripts.

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Light: Texture or Feature

One method of adding light that you may be familiar with is using the Full Bright and Glow settings that can be found in the Texture Tab. These settings don't actually add light, as such, but highlight the texture that has been applied to the prim. These effects don't actually add a light source to the prim. Depending on what you are building, this may be sufficient for adding light to your prim.

Texture Tab Features Tab

To add a true light source to our prim, we will use the Light settings that can be found in the Features Tab.

Before we start exploring how to use this feature, we need to do a quick check of the light settings in the SL Browser and the Environment Settings so that we can see the full Light effects.

On to the detour...

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Adjusting Your Browser for Light

1. Preferences Menu

To maximise the effects of the light we are going to add to our prim, we need to first check the Preferences settings for the SL browser.

Open up the Preferences window: Menu -> Edit -> Preferences

Edit Preferences Menu

Select the Graphics Tab

In the Lighting Detail settings (middle bottom section) make sure that the Nearby local lights radio button is selected, then click on the OK button to apply the changes.

This settings allows your browser to show light emitted from prims, otherwise, the only natural light from the sun and moon would be visible.

Note: The SL browser can only display light from a maximum of 6 sources: one source will always be the sun or moon, so that leaves only 5 other sources of light for you to see. That means that only the 5 nearest prims with Light features will have a visible light in your browser; the rest will appear unlighted. As your avatar moves around new lights will become visible as you approach them and others will fade and you move away from them.

2. Environment Settings

Obviously, if we are working with light features in bright daylight, we are not going to see much of the effects we are creating due to the strong natural light.

Never fear, SL has a solution for us. We can change the light from day to night by controlling the sun, all with a click of a button!

To change the light from the sun, make the following changes: Menu -> World -> Environment Settings -> Midnight

Let There Be Night

Instant darkness and star light.

As you test and adjust the light settings of your prim, feel free to switch between day and night, or stay in night mode if you like. As I always say, use the settings to create the building environment that suits your style; no one else can see it, so make it comfortable for you.

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Adding Light to a Prim

Now we are ready to start adding light to our prim: we have the Preferences set for Light, we know how to switch form Day to Night to see the light effects we are creating, Let There Be Light!

Rez a Sphere prim and give it a name in the General Tab. Switch to the Features Tab in the Edit window and tick the box next to the Light option.

Activate Light Setting in Features Tab

All done! We have now added the default light settings to our prim. Switch the light to Midnight and look at your prim. Your prim now emits light in the default white colour.

Default Light Feature

NOTE: This method of adding light to prims means that the light is always on. It cannot be turned off until you edit the prim and de-select the light setting in the Features Tab

The additional boxes under the Light option are no longer greyed out and you can tweak and adjust the available light settings to control how the light radiates from your prim.


This setting lets you select the colour of the light for your prim. Click on the coloured box to open up the Colour Picker window. Select the colour you want your light to be from the available swatches, or use the RGB/HSL fields to make your own custom colour and apply it. Changes take place immediately; notice how the colour you selected slightly alters the colour of your prim too.

Select Light colour


This setting allows you to set how strong you want the light to be. do you want a strong light, or a gentle glow? Intensity = 1.000 is full brightness, while lower numbers are good for dim ambiences like candlelight.

Light Intensity Setting


This setting allows you to set how far you want the light from the prim to reach. Do you want the light to emit as far as possible, or do you want a small circle of light to emit from the prim? The maximum radius of 20 m is suitable for a spotlight in a big room, while a smaller radius may be more appropriate for a smaller object like a table lamp, or even if you want to create subtle light effects.

Light Radius Setting


This setting allows you to set how you want the light to behave at the outer edges of its Radius. When you move away from the light, do you want it to suddenly disappear when you step outside the Radius distance, or do you want it to slowly start fading as you move towards the edge of the light Radius distance?

Falloff Light Setting

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Show Light Radius for Selection

This menu setting is found in the Tools menu and allows you to see how your changes to the above light settings will be emitted from the prim.

Show Light Radius for Selection menu option

When you activate this menu option, a bubble of light will appear around your prim. This light bubble will show you the behaviour of the light of the prim based on the settings you have made to Colour, Intensity, Radius and Falloff. Zoom your camera out and upwards to see the full light bubble you have created. Adjust the light settings as you need and check to see how they will impact the light bubble emitted from your prim.

The slides below show you the changes to the light bubble as I change the Light settings in the Features Tab.

Small Light Radius Large Light Radius

Some additional information on Light from the SL Wiki:

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Wrap Up

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Next Class: 8. Advanced Texture Techniques

Previous Class: 6. Flexi Prims

Class Project: Make a Lantern

Click on the image link below to go to the Project page with detailed instructions to make this Asian styled lantern.

Asian Styled Lantern

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