V-Ray Tip: VRay Emissives: Use VRayLightMtl for Look, Mesh Lights for Clean Illumination

Emissive materials are perfect for practicals, signage, screens, and neon. Use them intentionally to control look, noise, and performance.

• Use cases
  • Practical fixtures: LED strips, backlit panels, filament bulbs.
  • Design accents: neon tubes, light art, illuminated logos.
  • Devices: monitors, TVs, kiosks, dashboards.

Choose the right tool

• VRayLightMtl (emissive material): best for visible glow and GI contribution from luminous surfaces. Simple, fast for lookdev, not photometric.
• Mesh Light (convert geometry to a V-Ray Light): best for clean, noise‑free direct illumination with proper light sampling and LightMix control.
• Guideline: start with VRayLightMtl for the look; convert to Mesh Light when you need the object to actually light the scene (key/fill) or to tweak it in LightMix.

Clean renders with fewer samples

• Avoid many tiny emissive polygons. Merge geometry or convert to a Mesh Light to leverage multiple importance sampling.
• Increase the emitting area (wider strips/panels) for softer shadows and lower noise.
• Supplement trick: keep the visible emissive surface, but add a small invisible Rectangle Light near it to provide the primary illumination. This preserves the look and reduces noise.

Material settings that matter

• Use VRayLightMtl’s Color/Intensity to drive the look. If you work with a physical camera, enable “Compensate camera exposure” to maintain apparent brightness during exposure changes.
• For thin objects (neon, paper lanterns), enable back side emission to avoid dark back faces. For thick fixtures, keep it off to prevent light leaking.
• Avoid extreme multipliers that cause fireflies; prefer larger emitters or actual lights.

Color management and tone mapping

• Author emissive colors in linear space and preview through your chosen view transform (e.g., ACES). Highly saturated emissives can clip; reduce saturation or lower intensity to maintain detail.
• Use VFB Lens Effects (Bloom/Glare) instead of overcranking intensity. This yields controlled halos without blowing highlights.

Compositing and control

• VRayLightMtl does not participate in LightMix like regular lights. If you need per‑light post control, use Mesh Lights.
• Add Self-Illumination/Emission and GI/Lighting render elements. Grade emissive contribution separately; use Cryptomatte for precise masks.
• For signage/screens, layer a subtle diffuse/reflection material under the emissive to keep form and reflections present.

Performance checklist

• Instancing: repeat emissive fixtures as instances; convert repeated emissive meshes to a single Mesh Light where practical.
• Clamping: use highlight clamping carefully. Prefer reducing intensity or adjusting tone mapping to avoid losing dynamic range.
• Test with progressive renders and region updates; finalize with bucket/tiled rendering if memory is tight.

Procurement and learning

• Get the latest V-Ray builds and licenses from NOVEDGE for stability and improved sampling.
• Explore training, add‑ons, and compatible tools curated by NOVEDGE to refine emissive workflows in your host DCC.