Unity Version : 2019.2.17f1 HDRP Version : 6.9.2 Hey, I'm trying to get that sweet HDRP ambient occlusion working with my custom terrain system. My terrain is a single mesh object, rendered with a single transparent material. The material has a tileset texture with alpha used for clipping. Shadows are cast correctly by the clipped sprites used from the texture. I know ambient occlusion must work, because I have been using ambient occlusion in a previous unity version with the exact same mesh/texture with the help of unity's Post Processing Stack https://docs.unity3d.com/2018.3/Documentation/Manual/PostProcessing-Stack.html Now I'm just trying to do the same with the HDRP mode. Here is a screenshot of the problem : Intersections of walls and floors are supposed to be darker. You can clearly see the difference between AA ON/OFF on the right. I rendered both side by side in the example project for this comparison. From what we see, AA is supposedly configured to be visible on both objects but its not the case. Here is an example with an older version using unity's Post Processing Stack. Intersections for walls and floors are darker here. I tried : Switching form Forward Rendering to Deferred Rendering (and vice versa) Unchecking / Checking - Transparent Prepass Unchecking / Checking - Transparent Postpass Unchecking / Checking - After Postprocess Playing with Prepass/Postpass Clipping thresholds Using the demo project with everything configured And other options which I don't particularly remember Here is my global configuration : And here is my material configuration : Thank you for your time! Looking forward for all your recommendations !