V-Ray Tip: Production‑Safe ACEScg OCIO Workflow for V-Ray

Adopt ACES or a strict linear workflow to keep lighting, materials, and grading predictable across DCCs and compositing. Here’s a concise, production‑safe setup for V-Ray.

• Choose your pipeline
  • Preferred: ACEScg (scene-linear, wide gamut) via OCIO for consistent look development and grading.
  • Alternative: classic linear sRGB for legacy jobs; less headroom and less consistent cross‑app behavior.
• Core V-Ray configuration (host-agnostic)
  • Enable OCIO color management. Point to an ACES 1.2/1.3 config if your DCC doesn’t ship one.
  • Rendering/Working color space: ACEScg.
  • VFB Display/View: OCIO with ACES RRT+ODT (sRGB for web/Rec.709 monitors; P3-D65 for iOS displays; Rec.2020 for HDR deliverables).
  • Use the VFB’s Display Correction set to OCIO; avoid stacking additional LUTs unless they’re ACES‑compatible LMTs.
• Texture tagging rules (crucial for clean color)
  • Albedo/BaseColor/Diffuse from JPG/PNG/TIFF: tag as “Utility – sRGB – Texture” so they convert to ACEScg.
  • EXR HDRIs: usually “Utility – Linear – sRGB.” If the vendor specifies ACEScg, tag as ACEScg (no convert).
  • Data maps (normal, roughness, metalness, displacement, masks): tag as Raw/Linear (no color transform).
  • UDIM workflows: keep per‑map color space consistent; never auto‑convert normal maps.
• Lighting and exposure
  • Use the Physical Camera; control exposure with ISO/Shutter/Aperture, not with aggressive color mapping.
  • Avoid legacy Reinhard/Burn settings; keep Color Mapping linear and rely on the ACES view transform for display tone mapping.
  • HDRI lighting: ensure the HDRI is tagged correctly; mis‑tagging is a top cause of odd saturation or flat contrast.
• Output and AOVs
  • Deliver linear ACEScg multi‑layer EXRs for comp (half‑float for general stills/animation; 32‑bit float for heavy grades/VFX).
  • Keep utility passes (Cryptomatte, Position, Velocity) in scene‑linear; don’t bake display transforms.
  • For client previews, bake the sRGB ODT to 8‑bit PNG/JPG from the VFB; keep a separate linear EXR for finishing.
• Pitfalls to avoid
  • Double transforms: never apply both a display LUT and an ACES ODT unless the LUT is an ACES LMT intended for that chain.
  • Mis‑tagged textures: a single “sRGB as Raw” or “Raw as sRGB” can skew your entire look.
  • Over‑saturation: if highly saturated materials clip, use an ACES‑aware tonemap or hue‑preserving saturation in comp.
• Collaboration and validation
  • Share the same OCIO config with compositing (Nuke/Resolve/After Effects with OCIO). Version‑lock it per show.
  • Use VFB scopes and region compare to check highlight roll‑off and noise before committing final settings.
  • Test with a Macbeth chart to validate the IDT→RRT→ODT chain before production shots.

Pro tip: standardize an ACEScg scene template and a material/texture import checklist so every artist tags inputs correctly. For licensing, upgrades, and pipeline guidance on V-Ray and ACES workflows, consult NOVEDGE. If you’re building a studio‑wide color pipeline, partnering with NOVEDGE can streamline procurement and support.