Troubleshooting

intermediate troubleshooting

Radiant GI (Built-in) · Troubleshooting & FAQ

Solutions to common issues when using Radiant GI with the Built-in Rendering Pipeline.

No GI Visible

CauseFix
Camera missing the componentEnsure Radiant Global Illumination script is added to the active camera.
Volume not configuredSelect the Radiant Volume and verify a profile is assigned. Create or load one if empty.
Intensity too lowIncrease Indirect Light Intensity to 1.0 or higher.
Local volume out of rangeIf using Local mode, ensure the camera is inside the volume bounds.
Edit mode preview offEnable Show In Edit Mode in the Debug section to see GI outside Play mode.

Dark Objects Look Whitish (Forward Rendering)

In Forward rendering, the g-buffer does not provide albedo data. Dark surfaces receive the same indirect light as bright ones, making them appear washed out.

  • Best fix: switch to Deferred rendering path
  • Alternative: increase Luma Influence to use pixel brightness as a weighting factor

Flickering or Noise

  • Enable Temporal Filter (only active in Play mode)
  • Increase Smoothing to 3 or 4
  • Increase Max Samples (24–32)
  • Enable Binary Search for more accurate hits
  • Increase Jittering slightly (0.5–1.0) to break up banding patterns

Ghosting or Smearing on Moving Objects

  • Reduce Reuse Rays intensity or disable it (set to 0)
  • Increase Temporal Response Speed for faster adaptation
  • Increase Depth Rejection to discard stale temporal data

GI Fluctuates When Camera Rotates

This is inherent to screen-space techniques — objects leaving or entering the frustum change the available light data.

  • Enable fallbacks (Reuse Rays, reflection probes, or RSM) to stabilize off-screen contributions
  • Reduce Indirect Light Intensity to make fluctuations less noticeable
  • Use multiple Local volumes with tuned settings per area

Light Leaking Through Walls

  • For Virtual Emitters: set Box Center and Box Size to constrain the emitter to the intended room
  • For general GI: enable Limit to Volume Bounds in Artistic Controls to restrict GI to the volume area
  • Increase Thickness to prevent rays from passing through thin geometry

Performance Too Low

See the Performance Tips page for detailed tuning guidance. Quick wins:

  • Increase Downsampling to 2
  • Reduce Raytracer Accuracy
  • Keep Ray Count at 1
  • Reduce Max Samples and increase Jittering
  • Disable Reflective Shadow Maps if enabled

Stencil Conflicts

If certain objects (UI overlays, FPS weapons) incorrectly receive GI:

  • Enable Stencil Check in Artistic Controls
  • Configure the stencil mask value to match the objects you want to exclude
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