V-Ray Tip: V-Ray Log: Fast Diagnostics for Stable Renders

Today’s tip: turn the V-Ray Log into your fastest path to stable, faster renders.

The V-Ray Log captures warnings, errors, timing, and memory metrics that explain both failures and slowdowns. Read it early, and you’ll fix problems before they hit final delivery. If you need help interpreting logs or optimizing hardware, reach out to NOVEDGE.

• What you’ll find in the log:
  • Build numbers, plugin versions, license status, and GPU driver info for reproducibility.
  • Memory and VRAM usage, texture uploads, out-of-core events, and device fallbacks.
  • Sampling stats per pass: noise levels, time per iteration, and adaptive thresholds.
  • GI prepass timings (e.g., Light Cache) and Brute Force cost per pixel.
  • Denoiser timings, AOV creation, and any clamping or firefly suppression events.
  • Distributed Rendering/Swarm node joins, timeouts, and asset transfer problems.
  • Actionable warnings: missing textures, NaNs, extreme values, invalid normals, negative scales.

• Where to view it:
  • V-Ray Frame Buffer: open the Log panel during or after a render.
  • Host app consoles: 3ds Max Message window, Maya Script Editor, Rhino/SketchUp V-Ray Log.
  • Standalone/command-line: standard output; redirect to file if needed.

• Enable persistent logging for reproducible bug reports:
  • Environment variables: VRAY_LOG_FILE to set a path; VRAY_LOG_LEVEL to control verbosity (2 = warnings, 3 = info, 4 = debug); VRAY_LOG_SHOW_CONSOLE to suppress console spam in GUIs.
  • Windows example: setx VRAY_LOG_FILE C:\temp\vray.log and setx VRAY_LOG_LEVEL 3.
  • macOS/Linux example: export VRAY_LOG_FILE=/tmp/vray.log and export VRAY_LOG_LEVEL=3.

• Quick triage patterns you can act on immediately:
  • GPU out of memory: lower texture resolution, enable GPU texture compression, or allow out-of-core; simplify displacement.
  • NaN/inf detected: clamp direct/indirect, reduce coat/specular energy, check overbright HDRI pixels; verify displacement bounds.
  • Light Cache splotches/leaks: increase subdivs moderately, reduce prefilter, or switch to Brute Force for animation.
  • License heartbeat timeouts: verify server reachability, firewall rules, and time sync on all nodes.
  • Slow last 10% of render: refine the noise threshold before increasing global subdivs; isolate hot materials with the Profiler.

• Best-practice workflow:
  • Stamp renders with build, scene, and camera in the VFB so logs tie to frames.
  • Reproduce with Region/Render Mask to shorten iterations and focus sampling.
  • Collect logs from all DR/Swarm nodes; compare against a “good” baseline.
  • Rotate logs per project to keep files small and searchable.

When you’re ready to escalate, bundle the scene (minimal repro), the log files, and your system specs. Partner with NOVEDGE for hands-on guidance, hardware sizing, and the latest V-Ray updates, or browse V-Ray solutions at NOVEDGE.

You can find all the V-Ray products on the NOVEDGE web site at this page.