33.19.29 Lights Dialog Box

The Lights dialog box provides an interactive mechanism for placing colored, directional lights in a scene. See Section  29.2.6 for details about the items below.

Controls

Light ID   indicates the light that is being added, deleted, or modified. By default, light 1 is defined to be dark gray with a direction of (1,1,1).

Light On   indicates whether or not the light specified in Light ID is on or off. By turning off the Light On option for a particular light, you can remove this light from the display, while still retaining its definition. To add it to the display again, simply turn on the Light On button.

Direction   allows you to specify the direction of the light (the position on the unit sphere from which the light emanates) by entering the X, Y, and Z coordinates or by computing the coordinates based on the current view in the graphics window.

X,Y,Z   specify the direction of the light. For example, the direction (1,1,1) means that the rays from the light will be parallel to the vector from (1,1,1) to the origin.

Use View Vector   updates the X,Y,Z fields with the appropriate values for the current view in the active graphics window, and shines a light in that direction. Instead of entering the X,Y,Z values for a light's direction vector, you can use your mouse to change the view in the graphics window so that your position in reference to the geometry is the position from which you would like a light to shine. You can then click on the Use View Vector button to update the X,Y,Z fields with the appropriate values for your current position and update the graphics display with the new light direction. This method is convenient if you know where you want a light to be, but you are not sure of the exact direction vector.

Color   allows you to specify the light color with sliders. You can create your desired color by increasing and decreasing the slider values for the colors Red, Green, and Blue. You can also enter a descriptive string (e.g., lavender) in the Color field.

Active Lights   shows the position and color of all defined directional lights, and allows you to change the position of a light. All directional lights in ANSYS FLUENT are assumed to be at infinity and pass through the unit sphere at the position shown. All light rays arriving at the scene from one light are parallel. The colored markers on the surface of the sphere represent the color and direction of these distant lights. These lights point towards the center of the sphere (the origin, which is usually where the geometry is).

Lighting Method   specifies the method to be used in lighting interpolation: Off, Flat, Gouraud, or Phong. ( Flat is the most basic method: there is no interpolation within the individual polygonal facets. Gouraud and Phong have smoother gradations of color because they interpolate on each facet.) When Off is selected, lighting effects are disabled.

Headlight On   enables constant lighting effects in the direction of the view.

Reset   resets the light definitions to their last saved state (i.e., the lighting that was in effect the last time you opened the dialog box or clicked on Apply).