HPL3/Areas/Exposure Area

An Exposure Area is a box volume that changes camera tone-mapping values while the camera is inside it. It can be used to make the view adapt when moving between regions with substantially different brightness.

Exposure Areas are dedicated Level Editor objects. They are created through ExposureArea EditMode and are stored in the map's <map name>.hpm_ExposureArea track, not as an AreaType in .hpm_Area.

Create an Exposure Area

1. In the Level Editor, select ExposureArea EditMode.
2. Set the exposure, white-cut, and transition-time values for the new object.
3. Create a box covering the region in which those tone-mapping values should apply.
4. Select the object to adjust its position, rotation, size, or effect values.
5. Save and test the map while moving the camera across every boundary of the volume.

The edit-mode values apply to newly created Exposure Areas. After placing one, select that object before changing its individual settings.

Properties

Property	Serialized attribute	Purpose
Name	Name	Unique object name within the map.
Position	WorldPos	Center of the box in world space.
Rotation	Rotation	Rotation of the box volume.
Size	Scale	Dimensions of the affected box.
Exposure	Exposure	Target tone-mapping exposure. The existing editor reference documents that increasing it makes the image brighter and gives an editor range of -10 to 10.
White Cut	WhiteCut	Target tone-mapping white-cut value. Older documentation calls this setting WhitePoint; shipped map files and the current editor binary use WhiteCut.
Transition Time	TransitionTime	Time used to transition to the area's exposure settings.

Placement guidance

• Cover the entire region that needs the alternate exposure, including the camera's likely path rather than only the player's feet.
• Use a nonzero transition time when an immediate tone-mapping change would be distracting.
• Test both directions across the boundary. A value suitable when entering a dark room may expose an abrupt change when leaving it.
• Avoid unexplained overlap until the intended precedence has been tested. The shipped attributes do not record an editable priority value.
• Judge the result in-game with the final lights, fog, bloom, and color grading active; the numeric value alone does not establish the visual result.

Shipped examples

Six Exposure Areas occur in four inspected SOMA map tracks. Their values demonstrate that settings are scene-specific rather than universal defaults.

Map	Exposure	WhiteCut	TransitionTime
chapter00/00_01_apartment	-1.2	2.2	3
chapter00/00_03_laboratory	-1	4	2 or 1.9
chapter01/01_01_upsilon_awake	1	2.7	3

The laboratory map uses three separate volumes along part of the level, with the same exposure and white-cut targets and closely matched transition times. This is a useful example of applying consistent settings across multiple volumes, not a preset for other lighting conditions.

Shared HPL3 scope

The SOMA, Amnesia: Rebirth, and Amnesia: The Bunker Level Editor executables all contain the ExposureArea object and the Exposure, WhiteCut, and Transition Time controls. SOMA and Rebirth ship map tracks with the same three serialized effect attributes. No shipped Bunker Exposure Area was found, so the Bunker comparison establishes editor support rather than a campaign example.

Troubleshooting

• Nothing changes: confirm that the camera actually enters the box and that the saved .hpm_ExposureArea track contains the object.
• The change is too abrupt: increase Transition Time and retest both entry and exit.
• The scene becomes too bright or dark: move Exposure toward the map's surrounding value and evaluate it with the final lighting setup.
• The result clips bright parts of the image: adjust White Cut separately from exposure; they are distinct stored values.
• The effect disappears after copying a map: keep the .hpm_ExposureArea sidecar beside the main .hpm file.

See also

• ExposureArea EditMode reference
• Level-wide tone mapping settings
• SOMA areas