This article contains spoilers. Read at your own risk!
It might spoil your gaming experience when first playing the related games.
This testing element was originally unofficial as it was introduced in Portal: Still Alive, but later made official when it was implemented to Portal 2.
The Hard Light Bridge is a translucent but solid surface that can be redirected through portals to reach or serve as a blockade to certain areas.
Bridges may be emitted horizontally or vertically depending on the position of its emitter. Horizontal bridges can be walked upon, and players can continue seamlessly along them through any portals they pass (given enough headroom). Vertical bridges act more as portable walls that can be used as obstacles (for example, to intercept Weighted Storage Cubes).
In the cooperative campaign of Portal 2, ATLAS and P-body are sent to the Hard Light Bridge Factory in the Hard-Light Surfaces Testing Course. In the factory, it is revealed that the bridges, like the Sentry Turrets, are required to pass a quality monitoring before they can be put into testing. To achieve this, each emitter is attached to a support beam in a lineup, as the quality and strength of the surface is tested against a concrete wall.
The Mobility Gels are applicable on the bridge, allowing Test Subjects to use the gels in places where it normally would just fall through. ATLAS and P-body must utilize this method to pass one of the chambers of the Mobility Gels Cooperative Testing Course.
Behind the scenes
- The Hard Light Bridge was officially introduced briefly in a GTTV promotional showcase of Portal 2. At the time, the Hard Light Bridge possessed a texture similar to the one found in Portal: Still Alive. The texture has since changed and was given more detail.
- In Portal: Still Alive, the Hard Light Bridge was simply named as a "blue wall" by the signage found in the game files.
- In Portal 2, the emitters are made in the shape to that of Portal's Material Emancipation Grill emitters, which would further prove that the Hard Light Bridge was based on the testing element in Portal: Still Alive as the emitter was the Emancipation Grill model.
- The Hard Light Bridge appears to be similar in nature to the Combine Field Bridge.
- The Thermal Discouragement Beam is unaffected by Hard Light Bridges.
- According to the screens seen at the start of certain test chambers, the light used to create the bridges are absorbed through vast farm fields, then filtered to create the bridges. The field shown in this video resembles the field Chell is sent to at the end of the game.
- The Hard Light Bridge appears to be opaque to Sentry Turrets. Unlike glass, turrets do not appear to recognize Chell if she stands behind one; however, since the turrets appear to aim with infrared lasers, it could be argued that the light from the bridge interferes with a turret's ability to detect targets (as both are very close on the electromagnetic spectrum, as seen here).
- When standing near the bridge in the single-player campaign, Cara Mia can be heard playing slowly about 30 seconds into the audio file.
- They also hum in a similar fashion to the Robot Waiting Room tune used in the Perpetual Testing Initiative.
- Hard Light Bridges, unlike Thermal Discouragement Beams, will not pass through glass or clear panels.