Creating an Area Light Source

You can choose between four different types of area light sources: rectangular, disk, spherical and cylindrical.

1. Click Create Rectangle Area Light to create an area light source with a rectangular shape, just as a rectangular spot light would do:

   Note that the representation of the light source displayed above corresponds to the default representation mode (i.e. "wireframe display"). You can choose to display the light source in shading mode by selecting the corresponding option in Tools > Options > Infrastructure > Photo Studio > Display.
   You can also click:
   Create Disk Area Light to simulate spot lights, very useful for tuning the lighting of each object individually:
   Create Sphere Area Light to simulate a light bulb, but in a softer and more realistic way than the point light does:
   Create Cylinder Area Light to simulate neons, for instance:
   Each light source is identified by a specific symbol. To see the light symbol, click anywhere in the geometry area.
   Rectangle area light Disk area light Sphere area light Cylinder area light

2. As for ordinary light sources, you can interactively manipulate area light sources:

   the source point (1) rotates the surface around its target point the target point (2) rotates the surface around its source point the upper green manipulator translates and rotates the surface around its target point the lower green manipulator translates and rotates the surface around its source point.

   Note: this does not apply to punctual area light sources (i.e. sphere and cylinder) as they have no target point but only a source point.

3. Select the light then Edit > Properties and access the Lighting tab in order to edit lighting parameters:

   	The Type box lets you modify the source type by selecting a new type from the list: Spot, Point or Directional. However, changing the source type sets the surface type (under the Area tab) to "None" in order to avoid inconsistencies.

4. Use the slider to modify the color intensity, then click the button if you want to choose another color (the default color is white). Refer to Defining a Light Source for detailed information.

5. Define the light area Angle, the attenuation End as well as the attenuation Start Ratio and Angle Ratio. Refer to Defining a Light Source for detailed information.

6. Use the Falloff box to define the light energy attenuation. Refer to Defining a Light Source.

7. Access the Shadows tab then select the Ray Traced check box to enable shadow casting. When cleared, shadows are not calculated for this light source.

   Note: this option is used for rendering purpose only.

8. Access the Area tab:

9. Indicate the light area dimensions in the appropriate boxes, Length and Width in our example. You can either use the slider or enter the value directly in the field.

   The Type box lets you modify the surface type without using icons displayed in the Scene Editor toolbar. The other boxes are then modified accordingly. For instance, choosing a Sphere area replaces the Width, Length and Angle boxes with the Radius box. In addition to that, the source type (in the Lighting tab) is also modified to match the new surface type.

10. The Samples U, V boxes let you define the rendering sampling precision along the U and V axes. It is thus relevant for rendering purposes only.

    The lighting is computed according to the number of samples defined along the U and V axes: the more light sources, the less grainy the lighting. However, there is a price to pay in performance when defining a great number of samples. The maximum number of samples you can enter is 40, the optimum value being comprised between 7 and 10.
    	Once area light sources have been created, you can select or clear the Show Area check box to show/hide the selected light source when rendering the object. Note that the surface representation of a deactivated light source is also hidden in the geometry.

11. Click the Position tab to define the light source anchoring point and the point to which the source is directed, respectively in the Origin and Target areas.

    You can define this position in millimeters along the X, Y and Z axes.

    As far as Sphere and Cylinder area light sources are concerned, you just have to define the origin.

12. Use the Reference Axis area to define the light source position relative to the Model axis or to the Viewpoint. Refer to Defining a Light source for more information.

13. Click OK to validate your parameters.

More about area light sources

Area light sources created in the Photo Studio workbench are supported in:

• reviews created using DMU Navigator. Refer to the "DMU Review" section in the Version 5 - DMU Navigator User's Guide to for detailed information
• presentations created using DMU Navigator. Refer to the "DMU Presentation" section in the Version 5 - DMU Navigator User's Guide.