Creating and Editing Lights

on this page: steps | local lights | icons | headlight | performance | scope

You can create three kinds of lights with Cosmo Worlds: point lights, directional lights, and spot lights. Lights have various attributes, including color, location, direction (for directional and spot lights), intensity, and other type-specific attributes such as the beam width for a spot light. Use the Keyframe Animator to animate lights--the headlights on a moving car or a spot light that tracks an object, for instance.

Steps for Creating a Light

  1. Click the Create Global button to create a global light (or Create Local to create a local one).

  2. Click the button in the dialog box for the type of light you want to create: Point Light, Directional Light, Spot Light.

  3. Type a name for your light in the text box (optional but useful).

  4. Use the color wheel to select a color for the light. Left-drag on the small black box to the desired color.

  5. Use the slider bar to adjust the intensity of the light.

  6. For directional and spot lights, left-drag the blue arrow in the Direction window to change the direction of the light. (You can also manipulate the icon in the main window to change the light's direction.)

Note that if you have a number of lights in the scene, the pink name field in the chooser box indicates the active light for editing.

Local Lights

Local lights must be placed under a grouping node in the scene hierarchy. If the Create Local button is grayed out, you need to select the parent group for the object or create a parent group if one doesn't currently exist.

Click the "parent" up-arrow button to select the parent group, if there is one. If the Create Local button is still grayed out, choose Edit > Add Parent Group to create the parent group and enable the Create Local button.

Icons

Each light type has a different icon that appears in the scene at the light's location. The icon assumes the color of the light it represents. You can select a light icon and use the manipulator to position and orient the light. (The Quick Reference card shows the three light icons.)

Headlight

When a new scene is loaded, the headlight is turned on by default if the scene does not contain any lights. If a scene has lights, the headlight is turned off when the scene is loaded so that the effects of the lights are more visible.

A Word about Performance

Lights consume a considerable amount of rendering power, so they should be used in limited quantities in a given scene. A good rule of thumb is to include only two or three lights in a scene for satisfactory performance on most systems. Directional lights are scoped by their parent grouping node, so they scale well with large worlds.

Scope

Point lights and spot lights are always global in scope: they affect everything in the scene, no matter where they are in the hierarchy. Directional lights affect only the objects within their Transform grouping (to see the Transform containing a directional light, use the Outline Editor).

That's the general theory behind lighting. The effects of point lights and spot lights are limited by their radius, so they probably won't actually light up everything in the scene. (Some browsers may not implement this feature). In addition, on some browsers, directional lights are global as well.

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