In Active Worlds 3.0 and later world caretakers have control over the light sources in their world. They can also enable or disable fog. In Active Worlds 3.0 through 3.3, access to the fog and light source info was provided by the World Lights And Fog dialog, which was accessible from the Options Menu, but as of Active Worlds 3.4, you can access to these features through the Lighting section of the branching World Features dialog box, so a separate dialog box just for lighting and fog is no longer needed

The Directional Light

The directional light in the world is the light source that shines in a particular direction. It is used to approximate the light coming from an extremely distant light source, such as the sun. Generally speaking, polygons facing the directional light source will appear brighter than polygons facing away from it, although this does depend on the surface properties set for a particular polygon. Both the color and the direction of the directional light source can be adjusted.

Next to the name of each color setting in the Lighting section of the World Features dialog there is an image of the correctly selected color for that setting. To change a color setting, click on the representation of the color next to the name of that setting, to bring up a color picking dialog where you can interactively change the color. To disable the directional or ambient light source, simply set its color to black.

The direction of the world's directional light source is determined by the X, Y, and Z components of a vector. If you are not familiar with vectors this may be a little difficult to visualize at first. Simply put, the three components of the vector adjust how much the light points in each of three directions. The X component determines how much the light faces in the east/west direction, with positive values facing west. Similarly, the Z component determines how much the light faces in the north/south direction, with positive values facing north. Finally, the Y component determines how much the light faces in the up/down direction, with positive values facing up. Since directional lights typically shine "down" from "above", the Y component will usually be negative. Making the Y component positive will create a light that appears to shine up from below, as though the ground beneath you were glowing.

As an example, the following settings will create a directional light source that shines down at a about a 35.26 degree angle from the southwest corner of the sky:

X: -1.0
Y: -1.0
Z: 1.0

What matters is not the actual values themselves, but rather the relation of each value to the others, so the following settings will have the exact same effect as the example just given:

X: -5.0
Y: -5.0
Z: 5.0

The Ambient Light

The ambient light is a light source that shines on all polygons equally from all directions. The exact degree to which the ambient light effects the appearance of a particular polygon is determined by that polygon's ambient surface property. Since the ambient light is directionless by definition, only the color of the ambient light can be adjusted. For higher intensity, simply use a lighter color, and for lower intensity use a darker color.

Fog

Fog is a rendering effect that causes objects to become less and less visible as they recede into the distance, until ultimately they become invisible. It is sometimes used to hide the fact that you can't see objects beyond a certain distance anyway.

When enabled, fog has two parameters: the distance from the camera at which fog begins (the "minimum" distance) and the distance from the camera at which the fog effect reaches 100% (the "maximum" distance). Any objects that are beyond the maximum fog distance from the viewer are completely obscured and cannot be seen.

When fog is disabled, the "Fog Max" setting is still used to adjust the far clipping plane, beyond which objects will not be rendered.

Fog also has a "color" in the sense that as objects get further from the viewer they all begin to approach a uniform color. Fog in Active Worlds versions 3.0 through 3.3 used the current backdrop color as set in the World Features dialog as the fog color. As of Active Worlds 3.4, the fog color setting is separate from the 6 colors which can be independently set for a gradient color background effect. Keep in mind if you decide to use fog in your world, that objects will only be obscured with the single fog color, and not with the gradient background color. It is generally best to set these colors very similar to each other if you wish to achieve a realistic fog effect.

Usually the fog effect works best if there is no backdrop image in the world, (as set from the World Features dialog), because the fog will obscure objects in the distance, but will not obscure the backdrop. If you decide to turn fog on in your world, be sure to remove the backdrop image as well if it has not been specifically created to work with the fog you have planned. There may be cases where subtle combinations of both fog and a backdrop image which can be used to achieve certain effects, so the choice it left up to the world designers.