Urp Postprocessing

Help the user set up, configure, and debug post-processing effects using URP's Volume framework.

Goal: The user should have a working visual result with zero console errors after setup.

0. Prerequisite: an Editor you can run C# in

Volume profiles, VolumeParameter.overrideState, and the camera's post-processing flags are Editor/runtime object state, the checks and edits below all run C# inside a live Editor.

The unity-cli skill owns getting you there, installing the CLI, confirming a connected Editor, adding the project's com.unity.pipeline package, telling a genuinely absent Editor apart from one stuck in Safe Mode, and discovering the Editor's command catalog. Follow it first; don't re-derive any of it here. You need script eval in particular, not just a reachable Editor: its presence depends on the Pipeline package version, not on the CLI. If it's missing, say so and stop.

Run C# through the connected Editor with the script eval command. Discover its parameter shape from unity command --format json rather than assuming one, the inline form is unity command script eval --code '<snippet>', and some Pipeline versions also register script eval_file for running a snippet from a file. Check the catalog before reaching for script eval_file; it is frequently absent. unity command defaults to a 30 second timeout.

Passing C# to script eval

script eval compiles a statement block, not a file. Two consequences, both of which cause a compile error rather than a warning:

• No using directives. The compiler reads using UnityEngine; as a resource-disposal statement and rejects it (CS0210).
• Types must be fully qualified. A bare AssetDatabase or Volume does not resolve (CS0246 / CS0103), and a bare Object is ambiguous with object (CS0104).