Flinging

Flinging is a term used to describe a technique in which Portals can be utilised by the player in order to preserve (and increase) their momentum and reach otherwise-inaccessible areas. The concept of Flinging is first introduced in Portal Test Chamber 10, and is a fundamental technique in both Portal and Portal 2.

Technique
Flinging makes use of the player's momentum and velocity, and the way in which they are preserved when travelling through linked portals. The technique behind the most basic type of flinging is to place one portal on a vertical surface facing a chasm or obstacle, and another portal on a horizontal surface that is on a level below the player's current position. The player must then jump (or drop) through the second portal, and will then be flung through the first portal while preserving their velocity and momentum. In this way, the player is able to cross gaps or avoid other barriers that that they would otherwise be incapable of overcoming. This technique is first introduced in Portal Test Chamber 10.

Although the above technique is effective, it is not always practical, and this is especially true if the player is within a Test Chamber or area that has a uniform, or level, surface. In order to overcome this, the player must use more advanced flinging techniques. The second most common method of flinging requires the player to place one portal at the bottom of a high wall, and another portal at the top of the wall. The player must then enter the first portal and drop towards the floor, and recreate the first portal beneath them before landing. As with the previous technique, the player will emerge through the second portal while retaining the velocity and momentum acquired while dropping, and will be able to fling themselves past, or over, obstacles. This technique is used extensively in Portal Test Chamber 15.

The final flinging technique that must be used by players is typically utilised when the player only has access to horizontal portal-conductive surfaces. This technique requires the player to place one portal on the ground in an appropriate location, and then place a second portal on a horizontal surface on a level below the player's current position. As with the first technique, the player must then fall or drop into the second portal and emerge from the first. The key difference is that the portals must be alternated while the player is still in mid-air after passing through the second portal. Essentially, the player will emerge from the second portal that they have created and rise into the air before gravity forces the player to drop back through the portal. Before dropping through the portal however, the player must create a new portal on another surface and, after passing through it and rising into the air, must then recreate the first portal in another location. By repeating this process and alternating the creation of portals, the player can reach virtually any area as long as enough appropriately placed portal-conductive surfaces are present. This technique is called double flinging and is used extensively in the final area of Portal Test Chamber 18.