Raytracing

Referência

Panel:

Render ‣ Raytracing

The ray-tracing pipeline goal is to increase the accuracy of surface indirect lighting. This is done by generating ray from each BSDF and finding their intersection with the scene individually.

When disabled, it is replaced by a faster pipeline that uses pre-filtered light-probes. This fallback mode offers a more visually stable and optimized alternative when visual fidelity is not the primary goal.

Veja também

Limitations.

Method

Determine the tracing method used to find scene-ray intersections and indirect lighting.

Light Probe:

Use light-probe spheres and planes to find scene intersection. This option has the lowest tracing cost but relies on manually placed light-probes.

Screen-Trace:

Trace ray against the screen depth buffer. Fallback to light-probes if ray exits the view.

Resolução

Resolution at which the ray-tracing is performed. Lower options will be faster and use less memory but will produce blurrier results.

Screen Tracing

These settings control the behavior of screen space ray tracing. They are only available when Screen-Trace is the active tracing Method.

Precisão

Controls the precision of screen space ray tracing.

Higher values improve intersection accuracy and reduce artifacts, but decrease the maximum tracing distance and increase the performance cost.

Espessura

Controls how much thickness is assumed for surfaces represented by the depth buffer during ray tracing.

Higher values can reduce missed intersections, but may stretch reflections and increase flickering. Lower values provide more accurate intersections but may cause rays to miss thin surfaces.

Backface

Controls how rays that intersect the back side of visible geometry are handled.

When enabled, backface intersections are treated as valid hits instead of misses. This can reduce light leaking when using screen-space global illumination.

Radiance Scale

Controls how much of the front-face lighting is reused to approximate indirect lighting on backface hits.

Lower values reduce the contribution from backface hits, while higher values increase their influence.

Redução de ruídos

Denoising can be enabled to reduce the amount of noise from the raw ray-traced output. This can help image stability but will also over-blur the final ray-traced output.

Spatial Reuse

Reuse the rays from neighbor pixels. Can introduce some light leaks across surfaces.

Temporal Accumulation

Accumulate samples by re-projecting the last ray tracing results. This removes Fireflies but also introduces color bias. Useful for viewport temporal stability or making renders converge faster.

Bilateral Filter

Blur the resolved ray-traced output using a bilateral filter.

Fast GI Approximation

Fast GI Approximation is a fallback to the ray-tracing pipeline for BSDF with high roughness. It produces a less noisy output and captures bounce lighting more efficiently than individually traced rays.

This is currently implemented as a screen space effect and will inherit all associated limitations.

Ajuste

Maximum roughness a BSDF can have to use ray-tracing. BSDFs with higher roughness will progressively use the Fast GI Approximation. A value of 1 will raytrace every surfaces and disable the Fast GI.

Method

Determine the method used to compute the fast GI approximation.

Oclusão ambiente:

Use scene intersections to shadow the distant lighting from light-probes. This is the fastest option.

Global Illumination (Iluminação global):

Compute global illumination taking into account light bouncing off surrounding objects.

Resolução

Resolution at which the fast GI is computed. Lower options will be faster and use less memory but will produce blurrier results.

Rays

Number of GI rays per pixel at the specified Resolution. Higher values will reduce noise.

Passos

Number of screen samples per GI ray. Higher values will reduce the noise amount and increase the quality.

Dica

With a higher step count, there is less chance to miss other surfaces that could reflect or block the light. This means that the Fast GI Thickness parameters can be tweaked to lower values without losing too much light bounce energy.

Precisão

Higher values increase the precision of the scene intersections with the GI rays. Increased precision also increases performance cost.

Distância

If non-zero, the maximum distance at which other surfaces will contribute to the fast GI approximation.

Thickness Near

Geometric thickness of the surfaces when computing fast GI and ambient occlusion. Reduces light leaking and missing contact occlusion. The effectiveness decreases proportionally to the distance from the shading point, following the inverse square law.

Far

Angular thickness of the surfaces when computing fast GI and ambient occlusion. Reduces energy loss and missing occlusion of far geometry. Higher values will make the very thin objects block or reflect too much light.

Bias

Bias the shading normal to reduce self intersection artifacts.