Portal

A portal is a hole through timespace that allows for near-instantaneous travel between two points. Portals are created through the use of amati.

Function

Portals work by creating a link between two points in space. They are not a flat, 2-dimensional "hole", but a 3-dimensional space. It is common to speak about two portals being linked together, but in actuality, both sides of a portal are part of the same structure.

Any dalar can technically create a portal. However, it is extremely difficult for a single individual to do so; they simply don't have enough amati to safely open and sustain a portal. The strain of creating and passing through a portal is generally more than enough to cause a loss of consciousness, and thus is highly inconvenient for most situations. The larger the portal, the longer it's kept open, and the more people who pass through it (particularly humans, who have less natural protection than dalar), the more strain is put on the portal's creator, which can lead to lengthy loss of consciousness (lasting up to several hours) and a variety of fun side effects such as intense headaches, seizures, and even nerve damage. As a result, creation of portals by a single individual is strongly advised against.

For safer portal opening, multiple operators are required. Two well-trained dalar could safely open a short-term portal for the passage of a third dalar without risking loss of consciousness, but would be partly drained of amati. Three or four operators working in tandem could open a portal long enough for a half-dozen dalar to pass through. And a half-dozen dalar could open a portal for an army to pass through.

Opening a portal is the difficult part; in contrast, sustaining one is relatively easy. (This is why multiple operators allow for much larger, much longer-lasting portals--the initial burst of effort is split between the group, so all operators have plenty of energy left to sustain the portal.)

Interacting with a portal requires amati. In theory, this means that only dalar, humans, and animals can pass through unaided; inanimate objects, plants, electromagnetic waves, etc. must be wrapped in amati so they can pass through. In practice, small particles, electromagnetic waves, etc. occasionally pass through portals even without intentional amati usage, when natural amati happens to be in the right place at the right time.

Appearance

Because most electromagnetic waves cannot pass through unaided, even an open portal is not usually obvious. Spontaneous transmission of light waves means a portal will appear as a largely-transparent shape with variegated color. If one side is notably darker than the other, the "light" side's portal will appear to be shadowy, as light is transmitted to the "dark" side without much light being transmitted to the "light" side.

For convenience and to serve as a guideline for operators opening portals, permanent portal stations will use wooden or metal frames to outline the location of a portal.

Usage

Portals generally are created on a temporary, recurring, or (semi-)permanent basis. As with all amati constructs, portals are never truly permanent; they must be maintained or they will eventually fade away. However, if continually maintained, they can be semi-permanent, lasting as long as operators continue to power it. Some of the portals between major Sanmran cities have remained open for well over a hundred years, passing from operator to operator, although most portals are closed and reopened on a daily or weekly basis.

Portals can be set up against a wall to minimize necessary space, as if it is a 2-dimensional plane, but because a portal can be entered from any direction, high-traffic portals (such as in the Elten Portal Station) are set up such that passengers can enter and exit from at least two directions at once. (in theory, portals can be passed through from any direction, but more than two is awkward and more than four is not practical at all) To avoid collisions, one direction is designated as "entry" and one as "exit" for each side of the portal. In emergency evacuation situations--or simply very high traffic times of day--passengers could enter both designated directions.