V-Ray Tip: Export Equirectangular HDRIs from the V-Ray Frame Buffer

Turn your lighting setups into reusable HDRIs directly from the V-Ray Frame Buffer (VFB) and accelerate look development across projects. If you need V-Ray licenses or upgrades, check NOVEDGE.

Why do this:

• Capture your custom light rigs as portable, high-dynamic-range environments.
• Build a consistent lighting library for rapid scene tests and dailies.
• Bake LightMix-adjusted looks to share with your team or render farm.

Setup and capture (host-agnostic):

1. Position the camera at the lighting “sweet spot” (typically scene origin or subject center).
2. Set the camera to Spherical/Equirectangular:
   • Type: Spherical (Panorama).
   • Horizontal FOV: 360°, Vertical FOV: 180°.
   • Output aspect: 2:1 (e.g., 8192 × 4096 for 8K, 4096 × 2048 for 4K).
3. Keep exposure physically plausible:
   • Use a V-Ray Physical Camera with realistic ISO/shutter/f-stop, or control EV directly.
   • Disable “Clamp output.” You want the full dynamic range.
   • If needed, set a reasonable Max Ray Intensity to tame extreme fireflies without crushing highlights.
4. Simplify the capture:
   • Optionally enable a global material override so geometry doesn’t imprint shading into the HDRI.
   • Keep visible light cards (VRayLightMtl or visible area lights) if you want them baked in.
   • Use LightMix to balance color and intensity until the lighting feels right.
5. Render to convergence with Progressive, or finalize in Buckets for maximum cleanliness. Avoid heavy denoising; if you must denoise, apply it lightly to preserve highlight detail.

Saving from the VFB (for true HDR):

• Disable applying tone mapping/LUT on save. Do not bake display transforms (sRGB/ACES ODT) into the file.
• Save as 32‑bit float OpenEXR (.exr). Use ZIP (lossless) compression to reduce size without altering data.
• If your pipeline is ACEScg, save in ACEScg linear and set color space metadata accordingly; otherwise save in linear/sRGB primaries. Keep it scene‑referred.
• Optionally save snapshots of multiple LightMix states as separate EXRs to build variations fast.

Reusing the HDRI:

1. Create a V-Ray Dome Light and load the EXR (spherical mapping).
2. Enable Adaptive Dome Light for interiors or light-heavy scenes.
3. Match color space: if the EXR is ACEScg, set your VRayBitmap/Bitmap node color space to ACEScg.
4. Tune brightness with the Dome Light multiplier rather than re-exposing the EXR in 2D.
5. Use LightMix or Light Select AOVs on top for final on-shot tweaks.

Pro tips:

• Make “neutral” HDRIs by disabling GI and using a material override—ideal for unbiased relighting.
• Keep a consistent naming scheme with EV/scene size notes (e.g., “StudioSoft_8K_EV12”).
• For glossy-heavy scenes, enable “Affect Specular” on the Dome Light to ensure proper highlight response.
• Need more horsepower for building an HDRI library? Explore hardware and V-Ray options at NOVEDGE.

Deliverable checklist:

• 360×180 equirectangular EXR, 32‑bit float, no tone mapping baked.
• Optional LightMix presets and VFB color corrections saved separately for reference.
• Notes on intended exposure range and recommended Dome multiplier.

Build your own HDRI pack from project-proven light rigs and speed up every new job. For V-Ray subscriptions, renewals, or add-ons, see NOVEDGE.