Locality, which means that only a small volume around a surface contributes to AO.Dark halos or lack of occlusion behind foreground objects.If you have worked with screen-space ambient occlusion algorithms, you know the primary issues that they come with. At the same time, VXAO is 3-4x slower than HBAO+, while its results are much better than HBAO+. Obviously, it is much less resource intensive: computing VXAO for a frame can be 2-10x faster than computing full global illumination solution, depending on settings.

The idea is simple - we remove the lighting part and keep only the occlusion part. One of these features has been left with too little attention: the ambient occlusion mode, or VXAO as we call it. He began by reiterating how VXAO was designed. Unfortunately the slides haven't been published yet, but Panteleev divulged lots of information in a blog post on the official NVIDIA developer website. Alexey Panteleev, Senior Developer Technology Engineer at NVIDIA, was the lead engineer on VXGI (Voxel Global Illumination) and he also presented VXAO (which is derived from VXGI) during his Advanced Ambient Occlusion Methods for Modern Games GDC 2016 presentation.

This is the first real world application for VXAO, which NVIDIA considers the 'next step in ambient occlusion technology' beyond HBAO+. It's part of the GameWorks 3.1 update, along Volumetric Lighting and HFTS (Hyper Frustrum Traced Shadows). VXAO (Voxel Ambient Occlusion) was announced ahead of Rise of the Tomb Raider's launch and then added in a recent update, alongside support for DirectX 12.

Directx 12 vs opengl 4.4