HTrace Ambient Occlusion combines three of the most popular ambient occlusion techniques into a single asset, offering a highly scalable and adaptive system for AO computation.
HTrace: Ambient Occlusion HDRP v1.4.0 (Latest version)
HTrace: Ambient Occlusion HDRP v1.3.4 (17 Oct 2025)
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Description
Includes three AO modes:
▪ SSAO (Screen-Space Ambient Occlusion) – A lightweight and extremely fast method for occlusion gathering. It doesn’t require a denoiser and produces zero temporal lag.
▪ GTAO (Ground-Truth Ambient Occlusion) – Built on the latest advancements in ambient occlusion research, this technique works seamlessly with or without a denoiser, delivering the best possible quality in screen-space.
▪ RTAO (Ray-Traced Ambient Occlusion) – The most accurate occlusion method, utilizing hardware ray tracing for uncompromised quality and scalable performance.
Useful Links:
FAQ
Documentation
Comparisons with native GTAO and RTAO
Other HTrace Assets:
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MAIN FEATURES:
• Full Integration into the Rendering Pipeline: automatic resource injection that doesn’t require manual setup or package customization. HTrace overrides native ambient occlusion resources, ensuring compatibility with other rendering effects, as well as Forward and Deferred rendering.
• Scalability: choose between three different AO modes depending on your performance target or hardware requirements. Ranging from extremely fast SSAO to highly accurate RTAO, HTrace offers broad scalability options and exposes various parameters to fine-tune the effect to your needs.
• Cutting Edge Screen Tracing: GTAO mode utilizes an efficient horizon-based traversal algorithm to gather multiple samples in a single frame. Augmented with recent research on Visibility Bitmasks, it delivers accurate occlusion evaluation, even for complex surfaces, bridging the gap with its ray-traced counterpart.
• Real-Time Ray-Tracing: RTAO mode leverages contemporary hardware-accelerated ray tracing to achieve physically accurate results. With numerous performance controls, it efficiently computes high-quality occlusion without the typical performance cost associated with ray tracing.
– Sharp Upscaling: features an adaptive Lanczos filter, inspired by FSR technology and enhanced with bilateral weights, to interpolate half-resolution occlusion results without losing important details.
• Advanced Denoising: a modern denoising pipeline with configurable temporal and spatial stages. It includes motion rejection mechanisms to prevent ghosting and enables responsive temporal accumulation, coupled with reprojection filters that ensure sharp images during camera motion.
• VR Support: single-pass VR is supported for all three occlusion modes.
• Open Code: feel free to modify it. If you have any questions on how any part of it works you can always reach out to us on Discord.
Technical details
Currently supported APIs are: DX11, DX12, Metal (doesn’t support RTAO).
Currently tested HDRP versions are: 14 and above.
Currently tested Unity versions are: from 2022.2 to 6000.3
Limitations and Requirements:
RTAO mode requires Unity 2023.2 or above, a compatible API and hardware.
Orthographic Camera is untested and not guaranteed to work correctly.
MSAA is untested and not guaranteed to work correctly.
Unity LTS releases are recommended; bug fixes for non-LTS versions are not guaranteed.
