A directional light source simulates a very distant point light source. Its light rays are parallel to each other, as if emitted perpendicular from an infinitely large plane.

Diffuse Color

Specifies the diffuse color of the light. The color can be edited by clicking the color tile and using the Paint Tool Color window.

Intensity

Specifies the strength or brightness of the light source.

Scale

Scales the light icon in the 3D View. It has no effect on the light intensity. This can be useful when using large or small scale models in the scene.

Locked To Camera

Locks the position of the light source to the camera. When the camera is rotated or tumbled, the effect of the light (specular highlight) changes relative to the model’s surface.

Show Manipulator

Displays the light’s transformation manipulator. The manipulator that gets displayed depends on the light type. For a point light, a move manipulator appears to let you reposition the location in X, Y, Z. For a directional light source a rotate manipulator appears to let you rotate the direction of the light source.

Show Light

Displays the light’s icon to determine its location and direction depending on the light type. For a point light, a sphere icon appears. For a directional light a set of arrows appears to indicate the direction of the light source.

Shadows

The following describes the shadow properties for a directional light:

• Cast Shadows - Specifies whether the light casts shadows. (Point light sources do not cast shadows).
  NoteTo enable shadows for a model in the 3D View you must ensure both the Cast Shadows property (Light properties) as well as the Receive Shadows property (Material properties) on the assigned material are selected.
• Depth Map Bias - Offsets the depth map towards or away from the light. Adjust the Depth Map Bias only if you encounter the following problems: If dark spots or streaks appear on illuminated surfaces, gradually increase the value until the spots or streaks disappear. If a shadow appears to be detached from the shadow casting surface, gradually decrease the value until the shadow appears correct.
• Depth Map Resolution - Specifies the resolution of the light’s shadow depth map. Values are preset at 64 x 64, 128 x 128, 256 x 256, 512 x 512, 1024 x 1024, 2048 x 2048, 4096 x 4096. Increasing the depth map’s resolution increases the amount of texture memory on your computer’s graphics card and may affect interactive performance. In general, set the Depth Map Resolution to the lowest value that produces shadows of acceptable quality.