Specular Occlusion Mode The mode that HDRP uses to calculate specular occlusion. The options are:
• Off: Disables specular occlusion.
• Direct From AO: Calculates specular occlusion from the ambient occlusion map and the Camera's view vector.
• SPTD Integration of Bent AO: First uses the bent normal with the ambient occlusion value to calculate a general visibility cone. Then, calculates the specular occlusion using a Spherical Pivot Transformed Distribution (SPTD) that is properly integrated against the bent visibility cone.
• *Custom*: Allows you to specify your own specular occlusion values.