Ray tracing does not replace PBR. It evaluates the same BRDF with more accurate light paths. Screen-space reflections guess. A trace hits the actual scene. That is why a material that looked fine in raster lookdev can fail the moment you enable RT: the engine is finally showing the maps you authored. Prepare textures for that, instead of treating ray tracing as a new material model.
What ray tracing adds on top of PBR
You still plug albedo, roughness, normal, and metalness into the same slots described in the PBR textures complete guide. Tracing adds accurate reflections, refractions, and often better contact shadows. IBL still matters for the distant environment; RT fills what the cubemap cannot see. Keep a correct HDRI for the window and sky; see HDRI and PBR lighting.
Offline path tracers (Cycles, Arnold, V-Ray) have always done this. Real-time RT in Unreal, Unity HDRP, and Blender Eevee-next-style paths just made the same failures visible in the viewport.
Map errors RT will advertise
- Albedo with baked shadows: those shadows appear in reflections on nearby metals and never match the new light direction.
- Metalness 0.3–0.7: raster spec can hide it. A trace shows a dull, energy-wrong surface.
- Seams: a glossy wood floor mirrors the seam into the camera.
- Wrong normal convention: inverted bumps read clearly in reflected lighting.
- Over-strong normals on large tiles: RT reflections magnify wavy slopes on “flat” slabs.
Fix the maps. Do not add a second reflection capture to paper over a bad albedo.
Roughness is now a performance and quality knob
In many real-time RT implementations, roughness chooses a cheaper blur or a noisier trace. Very low roughness is expensive and honest. If a surface is not a mirror, give it 0.15–0.4 and a roughness map with variation. Brushed metal from the Locker3d catalog already has that variation; do not override it to 0 “because we have ray tracing now.”
Match resolution to how large the surface is in reflections. A tabletop that fills a chrome kettle may deserve 4K. A distant wall does not. Use the 1K–8K guide.
A lookdev loop for RT
- Approve materials under IBL without RT so base color and roughness are sane.
- Enable RT reflections only. Walk a chrome sphere through the set. Every surface the sphere sees is a texture that must tile and grade.
- Enable RT GI or shadows after reflections look clean. GI will then test albedo energy, not just spec.
- Denoise last. A denoiser on under-sampled RT spec will smear wood grain you spent hours placing.
Locker3d textures are free CC0, so you can clone a floor, rotate the UV, and overlay a second roughness to break RT-visible repeats. That is allowed; see CC0 what you can and cannot do.
What not to change
Do not switch to a non-PBR shader “for ray tracing.” Do not bake lighting into albedo because RT looks dark; fix exposure and GI. Do not drop metalness maps to save memory on hero metals that RT is meant to showcase. More material and lighting notes are on the blog.
Frequently asked questions
Do I need different PBR textures for ray tracing?
No. The same metalness/roughness set works. Ray tracing just shows reflections and contact more accurately, so baked lighting in albedo, mid-gray metalness, and wrong-resolution maps become obvious.
Why do tiled floors break under ray-traced reflections?
A visible seam or a repeating roughness cluster is mirrored across the room. Use seamless maps, vary roughness, and keep texel density even. Raising roughness to hide the tile is a last resort.
Should I raise texture resolution when I enable RT?
Only on surfaces that fill the reflection, such as a glossy floor or a hero metal. Most props can stay 2K. Follow the resolution guide instead of doubling every map.