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

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

eval

command. Discover its parameter shape from

unity command --format json

rather than assuming one — the inline form is

unity command eval --code '<snippet>'

, and some Pipeline versions also register

eval_file

for running a snippet from a file. Check the catalog before reaching for
eval_file
; it is frequently absent.

unity command

defaults to a 30 second timeout.

Passing C# to

eval

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
```
).

Where a snippet below is written as a file — with usings, for readability, or because it is meant to be saved into the project — qualify the types before passing it to

eval

0. Pre-Flight Checks

Before configuring any effect, verify all checks. Fix failures first.

URP is the active render pipeline — If not, inform the user and stop.
HDR is enabled on the URP Asset — Required for Tonemapping. Bloom works best with HDR; in SDR it still works but
```
threshold
```
must be < 1.
Camera has post-processing enabled —
```
renderPostProcessing
```
must be
```
true
```
(defaults to
```
false
```
). Camera Stacking: only a
```
CameraRenderType.Base
```
camera (or the last
```
Overlay
```
in the stack) should enable post-processing. Also verify the Renderer's PostProcessData asset is not null — if it is, the post-process pass won't exist.
The Volume's GameObject layer is in the Camera's Volume Layer Mask —
```
volumeLayerMask
```
defaults to layer 0 "Default" only. The Volume's
```
GameObject.layer
```
must be included, otherwise the camera ignores it.
Volume exists with
enabled = true
, a valid Profile, and at least one override — The
```
Volume
```
component must be enabled, have a non-null
```
profile
```
(or
```
sharedProfile
```
), and at least one
```
VolumeComponent
```
with
```
overrideState = true
```
on its properties.

Pre-Flight Check Snippet

Run this to verify the setup programmatically:

csharp

// `eval` compiles a statement block, not a file: no `using` directives are
// allowed, so every type is fully qualified.
var report = new System.Text.StringBuilder();

// 1. Check URP is active — a hard stop, so throw: it fails the eval loudly
var urpAsset = UnityEngine.Rendering.Universal.UniversalRenderPipeline.asset;
if (urpAsset == null)
    throw new System.Exception("URP is not the active render pipeline.");

// 2. Check HDR
if (!urpAsset.supportsHDR)
    report.AppendLine("Warning: HDR is disabled on the URP Asset. Tonemapping won't work; Bloom requires threshold < 1.");

// 3. Check camera post-processing
var cam = UnityEngine.Camera.main;
if (cam == null)
    throw new System.Exception("No Main Camera found.");
if (!cam.TryGetComponent<UnityEngine.Rendering.Universal.UniversalAdditionalCameraData>(out var camData))
    throw new System.Exception("Missing UniversalAdditionalCameraData on camera. Is URP active?");
if (!camData.renderPostProcessing)
    report.AppendLine("Warning: Post-processing is disabled on the camera. Enable via camData.renderPostProcessing = true.");

// 4. Check volume layer mask
var volumes = UnityEngine.Object.FindObjectsByType<UnityEngine.Rendering.Volume>(UnityEngine.FindObjectsSortMode.None);
foreach (var vol in volumes)
{
    if (!vol.enabled) { report.AppendLine($"Warning: Volume '{vol.name}' is disabled."); continue; }
    if ((camData.volumeLayerMask & (1 << vol.gameObject.layer)) == 0)
        report.AppendLine($"Warning: Volume '{vol.name}' on layer {vol.gameObject.layer} is not in camera's volumeLayerMask.");
    // 5. Check profile and overrides
    var profile = vol.sharedProfile;
    if (profile == null) { report.AppendLine($"Warning: Volume '{vol.name}' has no profile assigned."); continue; }
    if (profile.components.Count == 0)
        report.AppendLine($"Warning: Volume '{vol.name}' profile has no overrides.");
}

// Return the findings: logs land in the Editor console, the returned value comes back to you
return report.Length == 0 ? "Post-processing setup looks correct." : report.ToString();

1. Volume Setup

Effects are added as VolumeComponent overrides on a VolumeProfile (a

ScriptableObject

Global Volume (most common): GameObject with

Volume

component,

isGlobal = true

profile

assigned. Affects every camera whose

volumeLayerMask

includes the Volume's layer.

Local Volume (optional, but takes precedence): GameObject with trigger

Collider

Volume

component,

isGlobal = false

. Properties:

```
priority
```
(float) — higher values override lower when volumes overlap.
```
blendDistance
```
(float) — outer distance in world units to start blending from (0 = no blend, instant transition at collider boundary).
```
weight
```
(float, 0–1) — scales the volume's overall influence.

2. Post-Processing Effects

All effects are

VolumeComponent

subclasses added as overrides on a

VolumeProfile

via

profile.Add<T>()

. Check existence with

profile.Has<T>()

profile.TryGet<T>(out var t)

. Remove with

profile.Remove<T>()

Every property is a

VolumeParameter

. You must set

overrideState = true

before setting

value

, otherwise the Volume system ignores it.

When configuring a specific effect, load the full API reference:

references/effect-reference.md — All VolumeComponent properties by effect (Bloom, Tonemapping, ColorAdjustments, DepthOfField, Vignette, MotionBlur, FilmGrain, ChromaticAberration, SplitToning, LensDistortion, WhiteBalance, PaniniProjection, LiftGammaGain, ShadowsMidtonesHighlights, ColorCurves, ChannelMixer)

For code templates:

references/code-templates.md — Global Volume setup, camera post-processing, and profile modification templates

3. Anti-Hallucination Rules

Required Usings

These apply when you write a

.cs

file into the project. A snippet passed to
eval
cannot carry them — qualify the types instead (see "Passing C# to

eval

" above).

csharp

using UnityEngine.Rendering;           // Volume, VolumeProfile, VolumeComponent, VolumeParameter
using UnityEngine.Rendering.Universal;  // Bloom, Tonemapping, ColorAdjustments, UniversalRenderPipeline, etc.

Wrong → Correct API Mapping

WRONG	CORRECT
`PostProcessVolume`	`Volume` (from `UnityEngine.Rendering` )
`PostProcessLayer`	`UniversalAdditionalCameraData.renderPostProcessing` (bool)
`UnityEngine.Rendering.PostProcessing`	`UnityEngine.Rendering.Universal`
`profile.GetSetting<T>()`	`profile.TryGet<T>(out var t)` (returns bool)
`profile.AddSettings<T>()`	`profile.Add<T>()` (returns T; throws if already exists — check `profile.Has<T>()` first)
`volume.sharedProfile` (to modify at runtime)	`volume.profile` (auto-clones the asset into an instance)
`VolumeManager.instance.stack.GetComponent<T>()`	`volume.profile.TryGet<T>(out var t)`

Key Facts

overrideState = true
is required on every
```
VolumeParameter
```
you set. The volume system skips parameters where
```
overrideState
```
is
```
false
```
. This is the #1 scripting mistake.
sharedProfile
= returns the asset directly (edits persist to disk). profile
= auto-clones into an instance if needed (safe for runtime edits). Check with
```
volume.HasInstantiatedProfile()
```
.
profile.Add<T>(bool overrides = false)
— pass
```
true
```
to auto-enable
```
overrideState
```
on all parameters of the added component.

4. Debugging Checklist

When post-processing isn't working, check in order:

cam.TryGetComponent<UniversalAdditionalCameraData>(out var data)

succeeds and

data.renderPostProcessing

true

Volume exists in scene with a non-null
```
profile
```
(or
```
sharedProfile
```
) assigned?
Overrides added via
```
profile.Add<T>()
```
AND
```
overrideState = true
```
on each property you set?
Volume's
```
GameObject.layer
```
is included in camera's
```
data.volumeLayerMask
```
? (Default mask is layer 0 "Default" only.)
```
volume.isGlobal = true
```
(for global), or camera is inside the Volume's trigger
```
Collider
```
(for local)?
Camera
```
data.renderType
```
is
```
CameraRenderType.Base
```
, not
```
Overlay
```
? (Overlay cameras composite onto the Base camera's output.)

UniversalRenderPipeline.asset.supportsHDR

true

? Required for Bloom and Tonemapping.

Viewing in Game view? Scene view has a separate post-processing toggle in its toolbar.

5. Common Recipes

Format: Effect property=value. Bloom values are threshold/intensity/scatter.

Cinematic (Film): Tonemapping mode=ACES, ColorAdjustments contrast=15 saturation=-10, Bloom threshold=0.9 intensity=0.5 scatter=0.7, Vignette intensity=0.3 smoothness=0.4, FilmGrain type=Medium1 intensity=0.2

Stylized/Vibrant: Tonemapping mode=Neutral, ColorAdjustments saturation=20 contrast=10, Bloom threshold=0.8 intensity=1.5 scatter=0.6, SplitToning highlights=warm shadows=cool

Horror/Dark: ColorAdjustments postExposure=-0.5 saturation=-30 contrast=20, Vignette intensity=0.5 smoothness=0.3 color=dark-red, FilmGrain type=Large01 intensity=0.4, ChromaticAberration intensity=0.15

Clean/Mobile: Tonemapping mode=Neutral, ColorAdjustments postExposure=0.2, Bloom threshold=1.0 intensity=0.3 (subtle). Avoid FilmGrain, MotionBlur, DepthOfField on mobile.

6. Final Confirmation

After setup, report to user:

Post-Processing Setup Complete
- Volume: [Global/Local] on "[GameObject Name]"
- Profile: [Asset Path]
- Effects: [List with key property=value pairs]
- Camera: [Name] — renderPostProcessing=true, volumeLayerMask includes layer [N]

View results in Game view (not Scene view).
Undo all changes with Edit > Undo (Ctrl+Z).