# Spatial Filter ## Radius Defines the width of the spatial filter. Higher values lead to stronger noise reduction at the cost of small details and performance. *Performance impact: moderate, don't increase above the necessary level* {% tabs %} {% tab title="Radius = 0" %}

{% endtab %} {% tab title="Radius = 0.5" %}

{% endtab %} {% tab title="Radius = 1.0" %}

{% endtab %} {% endtabs %} [Spatial Occlusion ReSTIR Validation](https://ipgames.gitbook.io/htrace-ssgi/settings-and-properties/restir-validation#spatial-occlusion-validation) plays a very important role in preserving details during spatial filtering. Without it, over-blurring of small features (especially indirect shadows) becomes much more noticeable. \ The comparison below demonstrates the same **Radius** values, with [Spatial Occlusion ReSTIR Validation ](https://ipgames.gitbook.io/htrace-ssgi/settings-and-properties/restir-validation#spatial-occlusion-validation)turned off: {% tabs %} {% tab title="Radius = 0" %}

{% endtab %} {% tab title="Radius = 0.5" %}

{% endtab %} {% tab title="Radius = 1.0" %}

{% endtab %} {% endtabs %} ## Adaptivity Defines the adaptive behavior of the spatial filter. Higher values allow the filter radius to shrink more in corners and crevices (where small-scale indirect shadowing and light bounce are expected), better preserving details at the cost of filtering strength. *Performance impact: small* {% tabs %} {% tab title="Adaptivity = 0" %}

{% endtab %} {% tab title="Adaptivity = 1" %}

{% endtab %} {% endtabs %} Adaptivity, while efficient at preserving small-scale details, cannot replace [Spatial Occlusion ReSTIR Validation](https://ipgames.gitbook.io/htrace-ssgi/settings-and-properties/restir-validation#spatial-occlusion-validation). The best results are achieved when the two are used together: {% tabs %} {% tab title="0, OFF" %}

Adaptivity = 0, ReSTIR Spatial Occlusion Validation OFF

{% endtab %} {% tab title="1, OFF" %}

Adaptivity = 1, ReSTIR Spatial Occlusion Validation OFF

{% endtab %} {% tab title="1, ON" %}

Adaptivity = 1, ReSTIR Spatial Occlusion Validation ON

{% endtab %} {% endtabs %} ## Recurrent Blur Enables an algorithm that combines spatial and temporal denoising stages in a way that achieves stronger spatial blurring without a large performance impact. This comes at the cost of losing some details and slightly reducing temporal responsiveness. *Performance impact: small* ## Firefly Suppression Enables a filter that removes bright outliers ("fireflies") from the tracing result before the denoiser runs. This reduces boiling artifacts and improves temporal stability, at the cost of some image darkening. *Performance impact: small*