RTAO Quality Settings
Alpha Cutout (HDRP, Unity 2023.2+)
Defines how the Alpha Cutout property of materials will be handled:
Evaluate: Materials will accurately evaluate alpha cutout on hit. This matches Unity's native RTAO behavior, providing accurate alpha rendering at the cost of performance. If selected, HTrace will use Unity's Ray Tracing Acceleration Structure.
Depth Test: Alpha cutout will be evaluated in screen space against the depth buffer. Objects with alpha cutout that are obscured from the main view (e.g., offscreen or behind other objects) will behave as fully opaque. This option can improve tracing performance by up to 30%. If selected, HTrace will build its own Ray Tracing Acceleration Structure.
This selection is available only for HDRP and Unity 2023.2 and above. Other pipelines will default to Depth Test, while HDRP on older Unity versions will default to Evaluate.
Performance impact: severe, use Depth Test whenever possible.
Start with the Depth Test option and switch to Evaluate only if necessary, as the performance penalty of the latter may not be justified by its visual gains, especially if the occlusion radius is small or the number of objects with alpha cutout is limited.
Layer Mask
Use this option to exclude objects from the Ray Tracing Acceleration Structure on a per-layer basis. Excluded objects will become invisible to rays and will not cast ambient occlusion.
Ray Count
Specifies the number of rays launched into the scene to evaluate occlusion. This parameter represents the primary tradeoff between noise level and performance.
Performance impact: severe, use as few as possible
Cull Backfaces
Specifies whether rays can collide with the backfacing sides of polygons. This option is global and affects all surfaces, ignoring the "Double-Sided" material parameter. Disabling this option may slightly speed up tracing, as rays have a higher chance of finding hits earlier if they can collide with both sides of polygons. Enable this option if there are issues with non-closed geometry.
Performance impact: moderate, disable if not needed
In HDRP, this option is available only when Alpha Cutout is set to Depth Test. When the Evaluate option is selected, backface visibility for rays will be automatically determined on a per-material basis based on the Double-Sided material parameter.
Full Resolution
Determines whether the effect is rendered at full resolution or half resolution. This parameter has the greatest impact on performance. When disabled, all passes (except the final interpolation pass) are rendered with 4 times fewer pixels (2x downscaling along each axis). As a result, disabling Full Resolution can provide up to a 4x performance boost.
The visual quality difference between enabling and disabling Full Resolution depends on the upscaling parameters. For more details, refer to the Interpolation section.
Performance impact: most severe, disable if possible
Checkerboarding
Specifies whether the effect should be rendered using a checkerboard pattern, which processes only half of the pixels per frame. This option is designed to minimize visual impact while improving calculation times by up to 50%. It is recommended to enable this feature whenever possible. However, there are some limitations:
For Evaluate Alpha Cutout mode, Checkerboarding is available only starting from Unity version 2023.3.
Checkerboarding is available only when the Temporal Denoiser is active, as it relies on alternating checkerboard patterns between two consecutive frames.
The Motion Rejection parameter becomes less effective with Checkerboarding enabled, as it has 50% less data to process. Increasing the Motion Rejection value may be necessary in this case.
Checkerboarding is applied only to pixels with more than one frame of accumulated temporal history. Newly revealed (disoccluded) pixels are calculated in full resolution. As a result, the effectiveness of Checkerboarding may decrease during very fast motion or when many new surfaces come into view. For more details about temporal reprojection, refer to the Temporal Denoiser section.
Performance impact: beneficial, use whenever possible
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