Creating Object-to-Object Shadows

1. Create a spot light source by clicking Create Spot Light .

   Only spot light sources can cast shadows between objects. Object shadows are supported on Windows only and that we recommend the following graphic boards: Nvidia Quadro4 750XGL, Nvidia Quadro4 900XGL, ATI Radeon 8800 or Wildcat 6110. Object shadows are now fully compatible with CgFx shaders on Windows platform.

2. Access the lighting properties dialog box by right-clicking the light in the specification tree then selecting Properties.

3. Click the Shadows tab and select the On Objects check box to activate shadow casting between objects (in this case the option Enable OpenGL Shader is not selected in Tools > Options > General > Display > Performances tab, Miscellaneous area:

   If Enable OpenGL Shader option is selected in Tools > Options > Display > Performance tab, on selecting On Objects check box, the Color and Transparency fields are activated. Color: The color intensity of the shadow is modified using the slider. To change the color of the shadow, click the  button . A color palette allows you to change the color. Transparency: The transparency of the shadow can be changed by using the slider.
   	Right-clicking a light, then selecting Light On allows you to switch several spot lights on at a time. A maximum of eight light sources can be switched on at a time. Lights are not deactivated when the On Objects option (object to object shadow) is selected. It is recommended to use three light sources to project shadows at the same time. When On Objects is activated, the light source angle cannot exceed 45°. Inversely, defining a light source with an angle greater than 45° prevents you from creating shadows between objects.

4. Use the Map Precision list in the Properties dialog box to define the size of the shadow map: Small, Medium or Large.

   A shadow map identifies illuminated points in the scene with respect to a given light source. This ray-tracing technique relies on a precomputed depth map attached to the light source. The higher the map precision, the more accurate the shadows but bear in mind that there is a price to pay in performance and allocated memory.

5. Define the shadow Quality, which enables you to optimize the performance by selecting a value from the list:

   Standard: this is the default value. In that case, the shadow map is not recomputed at each interaction Good: the shadow map is recomputed at each interaction, which provides a more accurate shadow but affects performance.
   	We recommend that you start with a low precision and a standard quality then, when satisfied with your lighting parameters, increase Map Precision and Quality.

6. Click OK or Apply then OK to validate.

   The following are sample images showing shadows between objects On and Off:
   	Shadows Off
   	Shadows On with Enable OpenGL Shader not selected
   	Smooth Shadows On with Enable OpenGL Shader selected

Note that when On Objects is activated, shadows are cast on the environment as well (if there is one), even though the On Environment option is cleared.