Ambient Occlusion describes the shadowing and self-shadowing of objects. VRED uses precalculated ambient occlusion tosimulate shadows. Calculating it creates shadeows in gaps in a model, greatly improving the realism of the render.

For more information on the Ambient Occlusion, see the following:

• Simple ambient occlusion demo
• Ambient Occlusion Rendering

For videos, check out the following:

• Ambient Occlusion
• Ambient Occlusion OpenGL
• Screen Space Ambient Occlusion (SSAO)

The Bake Light and Shadows module is used for calculating ambient occlusion and Visualization > Ambient Occlusion Rendering is used for checking it.

1. With the geometry selected in the Scenegraph, select Scene > Bake Light and Shadows.

2. In the Direct Illumination section, click Ambient Occlusion and set the quality. The higher the quality, the more samples calculated.

3. Set the minimum and maximum distance to define the area in which the ambient occlusion is calculated.

   Tip:

   Try a distance between 1 and 3000 mm.

4. Click Calculate All to start the calculations. OpenGL immediately shows the calculated shadows.

Improving Shadow Quality

Ambient occlusion in VRED is based on vertices, so the quality of the shadows depends on the density of the geometry. Use the subdivision settings to improve model density, adding subdivisions where necessary. Also, don't forget to turn off your environment geometry (Dome), so it is not included in the ambient occlusion calculations.

1. In the Subdivisions tab of the Bake Light and Shadows module, activate subdivisions with Enable.
2. Select the preferred quality. The higher the quality, the purer the geometry is tessellated. We recommend starting with low quality.
3. Click Calculate All and check the results.
4. If the tessellation wasn't clean enough, change the quality to a higher setting and recalculate.

Shadow Plane Shadows

When calculating ambient occlusion and using a shadow plane on the ground, do the following before clicking Calculate All.

• With the ShadowPlane node selected in the Scenegraph, in the Material Editor > Shadow Material section, change Opacity Mode to Solid. This ensure the ambient occlusion shadow isn't dimmed due to the transparency of the shadow plane.
• Turn off your environment geometry (Dome) to speed up calculation time by not including this extra geometry.
• In the Subdivisions tab of the Bake Light and Shadows module, deactivate subdivision calculations by disabling Enable.

Checking Ambienct Occlusion

From the menu bar, use Visualization > Ambient Occlusion Rendering to check your results. Ensure the top node of the vehicle is selected and Wireframe is disabled. VRED automatically takes care of glass, so objects covered by glass are correctly calculated.