# Post-processing

> Grade the final image with exposure, tonemapping, bloom, ambient occlusion, fog, lens effects, ink outlines and toon shading.

Source: https://feather-engine.com/docs/rendering/post-processing/

Post-processing changes the final image. The project has one post-process volume that applies
everywhere, live in the viewport, in Play and in exported games. It covers exposure and
tonemapping, bloom, colour grading, lens effects, motion blur and anti-aliasing, and stylized ink
outlines. Fog and ambient occlusion are part of the environment, and toon shading is part of the
project's material settings.

## Apply a look

1. Open **Window → World & terrain → Post process**.
2. Under **Looks**, click a look to start from: Neutral, Stylized, Warm storybook, Vivid, Cinematic,
   Cold moonlight, Faded film, Dreamy or Noir.
3. Fine-tune the sections below. Each slider has a reset button that returns it to neutral.

![The Post process tab of World & terrain, with the Looks row and the Exposure & tone and Colour grading sections](../../../../assets/docs/rendering/post-processing.jpg)

**Stylized** combines toon-friendly grading, ink outlines and soft bloom. For a complete lighting
mood, including time of day and haze, use a lighting look instead; see
[Sky, weather and climate](/docs/world/sky-weather-climate/#apply-a-lighting-look).

## Exposure and tone

| Setting | Field | Panel range | Default |
| --- | --- | --- | --- |
| Tonemapping | `tonemapping` | TonyMcMapface, AcesFitted, AgX, BlenderFilmic, Reinhard, ReinhardLuminance, SomewhatBoring, None | TonyMcMapface |
| Exposure (stops) | `exposure` | −4 to 4 (−8 to 8 by command) | 0 |
| Auto exposure (eye adaptation) | `auto_exposure` | On/off | Off |
| Bloom threshold | `bloom_threshold` | 0–4 (up to 10 by command) | 0 |

Under **Bloom & exposure details**:

| Setting | Field | Range | Default |
| --- | --- | --- | --- |
| Bloom at strength 0 / at strength 1 | `bloom_intensity_min`, `bloom_intensity_max` | 0–1; 0–2 | 0.05; 0.35 |
| Bloom soft knee | `bloom_soft_knee` | 0–1 | 0.5 |
| Bloom scatter | `bloom_scatter` | 0–1 | 0.7 |
| Auto exposure min EV / max EV | `auto_exposure_min_ev`, `auto_exposure_max_ev` | −16 to 24 | −8; 8 |
| Adapt to dark / Adapt to bright (EV/s) | `auto_exposure_speed_brighten`, `auto_exposure_speed_darken` | 0.01–20 | 3; 1 |

The overall **Bloom** strength (0–1, default 0, which turns bloom off) and **Exposure stops** for the
Physical sky (−3 to 3 in the panel, −6 to 6 by command) are on the **Environment** tab and stored in
`project.environment` as `bloom` and `exposure_compensation`. Bloom strength maps onto the range set
by **Bloom at strength 0** and **Bloom at strength 1**.

## Colour grading

| Setting | Field | Panel range | Default |
| --- | --- | --- | --- |
| Temperature | `temperature` | −0.5 (cooler) to 0.5 (warmer) | 0 |
| Tint | `tint` | −0.5 (green) to 0.5 (magenta) | 0 |
| Saturation | `saturation` | 0–2 | 1 |
| Contrast | `contrast` | 0.5–2 | 1 |
| Midtone gamma | `gamma` | 0.5–2; above 1 darkens midtones | 1 |
| Shadows lift | `shadows` | −0.2 to 0.2 | 0 |
| Highlights gain | `highlights` | 0.5–1.5 | 1 |
| Hue shift ° | `hue` | −180 to 180 | 0 |

**Shadows**, **Midtones** and **Highlights** each have their own saturation, contrast, gamma, gain
and lift, multiplied onto the global values. **Midtones from … to** sets where the midtone range
starts and ends.

### Colour LUT

Pick a **Colour LUT** to grade with a lookup table, and blend it with **LUT intensity** (0–1,
default 1). A LUT is a strip PNG of N² × N pixels, for example 256 × 16. Import a `.cube` file
with `texture.import` and it is converted to a strip. Vignette, film grain
and the LUT run after tonemapping, so they appear in the player, screenshots and thumbnails.

## Lens

| Setting | Field | Panel range | Default |
| --- | --- | --- | --- |
| Vignette | `vignette` | 0–1 | 0 |
| Vignette softness | `vignette_softness` | 0 (tight) – 1 (wide) | 0.5 |
| Vignette roundness | `vignette_roundness` | 0 (follows the frame) – 1 (circle) | 0.5 |
| Vignette colour | `vignette_color` | sRGB | Black |
| Chromatic aberration | `chromatic_aberration` | 0–0.06 (up to 0.2 by command) | 0 |
| Depth of field | `depth_of_field` | On/off | Off |
| Focus distance m | `focus_distance` | 0.5–200 m | 12 m |
| Aperture f-stop | `aperture` | 0.8–22 | 2.8 |
| Bokeh highlights | `bokeh` | On/off | Off |

## Motion and quality

| Setting | Field | Range | Default |
| --- | --- | --- | --- |
| Motion blur | `motion_blur` | 0–1, the camera shutter angle | 0 |
| Anti-aliasing | `anti_aliasing` | Msaa, Smaa, Taa, Fxaa, None | Msaa |
| Contrast-adaptive sharpening | `sharpening` | 0–1 | 0 |

Players can lower depth of field, motion blur and TAA with the Low graphics setting. Some effects
replace MSAA with SMAA or TAA: ink outlines, screen-space reflections, bounce lighting and
volumetric clouds.

## Ink outlines and film grain

Ink outlines draw cel-shaded lines around shapes and creases. They are in **Reflections and film**.

| Setting | Field | Panel range | Default |
| --- | --- | --- | --- |
| Ink outlines | `outline` | 0 (off) – 1 | 0 |
| Outline thickness (px) | `outline_thickness` | 0.5–6 | 1.5 |
| Outline colour | `outline_color` | sRGB | Near black |
| Silhouette threshold | `outline_depth_threshold` | 0.005–1; lower draws more lines | 0.08 |
| Crease lines | `outline_crease` | 0–0.3; 0 turns creases off | 0.02 |
| Outline fade (m) | `outline_fade_distance` | 5–1,000 m | 220 m |
| Film grain | `film_grain` | 0–1 | 0 |
| Grain size (px) | `grain_size` | 1–8 | 1.5 |

Screen-space reflections and bounce lighting are covered in
[Lighting](/docs/rendering/lighting/#reflections-and-bounce-lighting).

## Ambient occlusion

Turn on **Ambient occlusion (SSAO)** in the Post process tab, or **Ambient occlusion** on the
Environment tab. It is off by default.

| Setting | Field | Range | Default |
| --- | --- | --- | --- |
| SSAO quality | `ssao_quality` | Low, Medium, High, Ultra | High |
| SSAO thickness (m) | `ssao_thickness` | 0.01–4 m; thinner gives less halo | 0.25 m |

## Fog

Feather Engine 2 has three kinds of fog:

- **Distance fog** fully hides the world at **Fog distance m** on the Environment tab (20–2,000 m
  in the panel, up to 5,000 by command, default 235 m). The weather thickens it, and the horizon
  settings can push clear-weather fog out to the edge of the view; see
  [Landscape](/docs/world/landscape/#streaming-and-distance).
- **Volumetric fog** is a box of raymarched fog around the camera, lit by the sun or moon and by
  lights marked **Volumetric**. Turn it on under **Volumetric fog** on the Environment tab.
- **Fog volumes** fill one object's box with volumetric fog. Add one with **Add Component → Fog**.

| Volumetric fog setting | Panel range | Default |
| --- | --- | --- |
| Volumetric fog (light shafts and halos) | On/off | Off |
| Fog colour | sRGB | Pale blue |
| Density | 0–0.5 | 0.06 |
| Scattering | 0–1 | 0.35 |
| Absorption | 0–1 | 0.3 |
| Shaft directionality | −0.95 to 0.95 | 0.55 |
| Sun/moon in fog | 0–10 | 1 |
| Ambient in fog | 0–2 | 0.1 |
| Quality (steps) | 4–256 | 48 |
| Box half-width m | 5–500 | 90 |
| Box height m | 1–300 | 30 |
| Box floor m | −100 to 100 | −4 |

The Low graphics setting turns volumetric fog off.

## Toon shading

Toon shading bands the light from directional lights, including their shadows, into a few soft
steps, tints the shade, and adds a rim light and a stylized highlight. Base colour textures, vertex
colours, normal maps, alpha and emission keep working. Other lights, the sky and ambient light reach
the surface unchanged.

1. Open **Window → Materials & textures** and select the **Project shading** tab.
2. Turn on **Toon by default** to draw imported models, and every material on **Project** shading,
   with toon shading. Materials set to **Standard** or **Toon** keep their choice.
3. Pick a **Preset**, then adjust the look.

| Setting | Field | Range | Default |
| --- | --- | --- | --- |
| Light bands | `bands` | 1–6 lit steps | 2 |
| Band softness | `softness` | 0 (hard ink) – 1 (smooth) | 0.12 |
| Shadow tint | `shadow_tint` | sRGB; white keeps the shade neutral | Cool blue |
| Rim colour | `rim_color` | sRGB | Warm white |
| Rim width | `rim_width` | 0–1 | 0.32 |
| Rim strength | `rim_strength` | 0–4 | 0.45 |
| Highlight size | `specular_size` | 0–1 | 0.25 |
| Highlight strength | `specular_strength` | 0–4 | 0.3 |

| Preset | Look |
| --- | --- |
| Storybook | The defaults |
| Hard cel | One hard band, deeper shade, stronger rim |
| Soft painterly | Three soft bands, gentle rim |
| Warm sunset | Warm rim light |
| Flat | One band, no rim and no highlight |

A material can override the project look; see [Materials](/docs/rendering/materials/#shading).

:::note
Toon materials render forward. Screen-space reflections and bounce lighting do not apply to them,
but ambient occlusion, fog and baked light probes do.
:::

## Limits

- One post-process volume per project.
- Depth of field, motion blur, TAA, volumetric fog and bounce lighting are reduced or off on the Low
  graphics setting.
- A LUT must be a project texture in the N² × N strip layout.

## Automate it

This loads the Stylized look, adds a warm grade and a vignette, and turns on toon shading for the
whole project:

```bash
feather-cli --connect .feather-session.json command project.post_process \
  --json '{"preset":"Stylized","temperature":0.15,"vignette":0.3}'

feather-cli --connect .feather-session.json command material.set \
  --json '{"patch":{"toon_by_default":true,"toon_preset":"Soft painterly"}}'
```

| Command | Purpose |
| --- | --- |
| `project.post_process` | Patches the post-process volume; `preset` loads a look first |
| `project.environment` | Patches bloom strength, ambient occlusion, exposure stops, fog distance and volumetric fog |
| `material.set` | Patches the project's toon shading |
| `scene.update` | Adds or edits a `fog` volume on an object |
| `texture.import` | Imports a PNG or converts a `.cube` LUT |

See [Agents & automation](/docs/agents/overview/) for connecting a live session.