光线追踪

参考

面板:

渲染 ‣ 光线追踪

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.

See also

限制。

方法

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

光照探头:

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

屏幕追踪:

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

分辨率

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

Max Roughness

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.

屏幕追踪

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

精度

Higher values increase precision of the screen space ray-tracing but lower the maximum trace distance. Increased precision also increases performance cost.

厚（宽）度

在追踪过程中纳入深度缓存器内计算的像素厚度。较高的数值会将反射像素拉伸并增加闪烁。较低的数值可能会导致物体表面反射被裁剪或消失。

降噪

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.

空间复用

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

时序累积

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.

双边过滤

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

快速GI近似

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.

方法

Determine the method used to compute the fast GI approximation.

环境光遮蔽:

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

全局照明:

计算全局照明，考虑周围物体的反弹光线。

分辨率

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

光线数量

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

步数 (阶梯)

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

Tip

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.

精度

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

距离

如果非零，则其他曲面将有助于快速GI近似的最大距离。

厚度 近端

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.

远端

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.

偏移

偏移着色法向以减少自相交伪影。