| Problem | Why it happens | "Full" Fix | | :--- | :--- | :--- | | | Specular highlight on a thin edge | Turn on Subpixel Mapping and Clamp Output to 5. | | Black splotches on ceiling | Irradiance map too low | Switch to Brute Force as Primary GI. | | Blurry shadows | Light Cache Sample size too high | Reduce Sample Size to 0.015 . | | Glass looks black | Ray Depth is too shallow | Set Max Depth (Refract) to 24 . | | Render stuck at "Building Light Cache" | Too many emissive materials | Replace emissive with actual rectangle lights. |