Blender EEVEE Ray Tracing Guide: The Right Settings for Interior Renders

Blender’s official EEVEE documentation explains how ray tracing and material settings affect indirect lighting, reflections, transparency, and performance. This guide offers a step-by-step way to assess the options in the current Blender manual for architectural interior scenes. The documentation does not specify a Blender version number, so it is not possible to infer which version introduced these settings.

1. Choose the method and resolution

1. Open the Render › Raytracing panel. Ray tracing aims to improve indirect lighting accuracy by calculating how rays emitted from surfaces interact with other surfaces in the scene. When this feature is disabled, EEVEE switches to a faster rendering path that uses prefiltered light probes. This alternative may be more stable and efficient in scenes where visual accuracy is not the top priority.

2. Choose the option that best suits the scene under Method. Screen-Trace uses screen-space depth information and falls back to light probes for rays that extend beyond the viewport. The Light Probe method approximates scene intersections using probe spheres and planes. The documentation describes it as the option with the lowest tracing cost, but the result depends on manually placing the probes in the scene.

3. Balance memory use and image sharpness when choosing Resolution. Lower resolution renders faster and uses less memory, but can blur the ray-traced result. For this reason, lowering the setting requires a final image check, especially in shots where reflections and indirect light are important.

2. Check screen-space traces and light leaks

1. If you’re using Screen-Trace, increase Precision only in response to visible intersection issues. More precise calculations may reduce some tracing artifacts, but come at a performance cost and shorten the maximum distance rays can travel. So higher precision does not always mean that a wider area will be calculated accurately.

2. The Thickness setting determines how thick surfaces represented in the screen-space depth buffer are assumed to be during tracing. Increasing the value may reduce the chance of rays missing thin surfaces. However, treating surfaces as too thick can extend reflections and cause flickering. Lower values can help locate intersections more accurately, but increase the risk of missing thin geometry altogether. The documentation does not recommend a fixed value for this setting.

3. If you see light leaks in screen-space global illumination, try the Backface option. When enabled, rays that intersect the back side of visible geometry are not treated as wasted; this behavior can reduce light leaking between surfaces. Radiance Scale controls how much lighting information from the front surface contributes to intersections on the back surface. A lower value reduces this contribution, while a higher value strengthens it.

3. Evaluate denoising and Fast GI options

1. If noise in the raw ray-traced result is distracting, use Denoising. It can make the image more stable, but excessive smoothing can also suppress surface detail. Check whether fine edges and material textures are preserved.

2. Observe the potential side effects of each denoising method separately. Spatial Reuse takes ray results from neighboring pixels into account and may cause unwanted light transfer between different surfaces. Temporal Accumulation combines information from previous ray-traced frames with the new result. This can remove isolated bright spots, but may cause color shifts. The documentation also considers this method useful for temporal stability in the viewport or for helping a render converge faster. Bilateral Filter is the filter option that applies blur to the calculated ray-tracing image.

3. Consider Fast GI Approximation for highly rough surfaces. Rather than tracing each ray individually, this option aims to produce a less noisy result and calculate bounced lighting more efficiently. Ambient Occlusion shadows distant lighting from light probes according to scene intersections and is the fastest of the two options. Global Illumination also accounts for light reflected from surrounding objects. Since both methods are screen-space effects, they share the limitations of this approach.

Threshold determines the roughness level up to which ray tracing is used; materials above the threshold gradually switch to the Fast GI approach. The documentation associates a value of 1 with ray tracing on all surfaces and Fast GI disabled. Lowering the Fast GI resolution reduces processing and memory use, but can blur the image. Increasing the number of Rays reduces noise. Increasing Steps can also reduce noise and improve quality; more screen samples reduce the chance of missing surfaces that reflect or block light. Higher Precision values improve intersection accuracy, but come at a performance cost.

4. Transparency and thickness for interior materials

1. For glass and other transparent surfaces, choose a Render Method under Properties › Material › Settings based on your workflow. Dithered allows grayscale dithered transparency and supports render passes and ray tracing. Materials are rendered in layers, so a layer can only transmit light from layers in front of it. When there are no intersections with lower layers, ray-traced transmission relies on light probes.

2. Blended can provide colored transparency, but cannot be used with render passes or ray tracing. The blending order of transparent objects can also change the final color. EEVEE sorts them by object origin, at the object level rather than per pixel or triangle. In scenes with thousands of objects, this sorting can become costly. The Transparency Overlap option, available only for Blended, can also be adjusted: when enabled, all transparent fragments are rendered; when disabled, only the frontmost surface fragments are used. Turning it off may help with sorting issues.

3. Set Thickness according to the geometry represented by the material. This setting approximates an object’s internal structure without expensive calculations and is used for effects such as subsurface scattering, translucency, and refraction. If no value is connected, the default thickness is based on the object’s smallest dimension. A value of zero disables this approximate internal thickness, and the surface is treated as a single interface. For large or compound meshes, such as vegetation, it is more appropriate to use the thickness of individual parts, such as leaves or blades of grass, rather than the size of the entire object. The documentation also notes that thickness can be baked into textures or custom attributes for more accurate results.

What does this mean for architectural and archviz workflows?

These controls matter particularly in interior scenes with glass partitions, thin finishes, indirect lighting, and rough surfaces. Resolution can be reduced for speed, but the effects on blur and memory savings should be assessed together. The choice of transparency method should also be made early in scene setup, taking compatibility with render passes and ray tracing into account. The official documentation does not specify hardware requirements or licensing conditions, so it is not possible to derive version or system recommendations on those matters.

Common mistakes

• Assuming that increasing Precision also increases how far rays can travel. The documentation says the distance may become shorter.

• Overlooking the possibility of extended reflections and flickering when increasing Thickness.

• Judging denoising only by how clean the image looks; excessive filtering can soften details.

• Choosing a material method without accounting for the compatibility differences between Dithered and Blended.

• Assuming that one general thickness value will suit all thin parts in compound geometry, such as vegetation.