The Universal Render Pipeline (URP) is a scriptable pipeline that provides great flexibility but also requires settings to be correct for features to work. If a spotlight isn't functioning within Unity while using URP, here are some possible causes:
Incorrect Layer Settings: The spotlight may not be illuminating objects on layers that are not included in its culling mask.
Shader Issues: Non-URP shaders won't work correctly under URP. If the materials in your scene are using non-URP shaders, they might not respond to lighting as expected.
Improper Light Settings: There might be issues with the spotlight settings themselves, such as incorrect range, angle, or intensity.
Lighting Limitations: URP has a limit on the number of pixel lights that can be rendered at once, which if exceeded, additional lights will fall back to vertex lighting or be ignored altogether.
Graphics Settings: If the graphics settings for the project don't include the URP asset or are misconfigured, then certain features like lighting may not work properly.
Renderer Features: In URP, Renderer Features could be disabled or improperly configured, leading to issues with rendering light sources.
Solution - Here's How To Resolve It
To resolve the 'unity urp spotlight not working' error, try the following solutions:
Layer Configuration: Ensure that your spotlight is set to illuminate the correct layers by adjusting its culling mask.
Shader Compatibility: Convert all materials to use shaders compatible with URP, using the built-in material upgrader found under Edit > Render Pipeline > Universal Render Pipeline.
Adjust Spotlight Settings: Tweak the spotlight’s angle, range, and intensity to ensure it's capable of affecting the scene as intended.
Modify Light Limit: Go to the URP asset settings and increase the maximum number of pixel lights if you are reaching the limit, or adjust the light importance via the Editor to prioritize which lights should be pixel lights.
Check Graphics Settings: In the Project settings under Graphics, make sure that your URP asset is assigned as the current Scriptable Render Pipeline asset.
Renderer Features Check: Verify that any custom Renderer Features are enabled and configured correctly within the URP Forward Renderer data asset tied to the camera that's rendering the scene.
By systematically going through these areas and ensuring the configuration is correct, the spotlights in a URP-based Unity project should function as expected.