Blender Needs Trace Filters — Let Lights Bypass Blocking Objects

Problem Summary

In Blender 4.3+, Light Linking lets you include or exclude objects from lighting, but it does not prevent lights from being physically blocked, reflected, or refracted by excluded geometry like glass. This makes precise lighting behind transparent or refractive surfaces impractical.

Use Case: Product Visualization (Watches) Lighting a reflective dial, which sits behind glass, often requires a specific grazing angle to reveal material details like brushed metal or subtle reflections.

That angle typically causes the light source itself to appear as a highlight in the glass.

You can exclude the glass via Light Linking, but:

The glass still physically interacts with the light (reflects/refracts), blocking the dial or creating glare.

Result: You can’t light the dial cleanly from that angle without compositing workarounds or fake geometry.

Proposed Solution Introduce Per-Light Occlusion Filtering (aka Trace Filters / Ray Masks):

Suggested Implementation: Light Settings: Add an “Ignore Occlusion From:” object/collection selector

Object Settings: Add per-light occlusion toggles in ray visibility

Light Linking: Extend with an “Exclude From Occlusion” toggle

Why It Matters ✅ Enables clean, single-pass lighting through glass ✅ Eliminates complex hacks (multi-pass, fake geometry, shader tricks) ✅ Critical for high-end product, automotive, jewelry, and watch visualization ✅ Aligns Blender with industry-standard lighting control (Arnold, Redshift, Clarisse)

Existing Software Comparison Software Feature Name Purpose Arnold Trace Sets Control which objects light rays hit Clarisse Ray Masks Full per-light, per-object ray masking Redshift Light Exclusion Remove object from occlusion/shadow C4D Include/Exclude Classic occlusion control per light

Request Summary Add per-light occlusion controls in Cycles (and Eevee-Next later)

Provide UI/API to exclude geometry from blocking light rays, not just receiving them

✅ Support Available Test .blend files ready

Node setups and before/after renders available