**Specular Occlusion Mode** The mode that HDRP uses to calculate specular occlusion. The options are:
• **Off**: Disables specular occlusion.
• **From AO**: Calculates specular occlusion from the ambient occlusion map and the Camera's view vector.
• **From AO and Bent Normal**: Calculates specular occlusion from the ambient occlusion map, the bent normal map, and the Camera's view vector.
• **Custom**: Allows you to specify your own specular occlusion values.