UFO interception questions

[Zesty]

Hello. Long time X-Com player here. Wondering about a few things:

1. What all goes into deciding whether a UFO gets away during interception? It seems like all x-com craft always close in to combat range at the same rate regardless of the x-com craft's speed, regardless of the UFO's current speed on the map, and that UFOs then simply escape at a semi-random time. What factors go into this?

2. Is there any good way to guess whether a UFO will land or not? Sometimes I see UFOs slow down and stay very low but never land. Obviously assaulting intact UFOs is preferred but its quite annoying when you let one get away because you were waiting for a landing. Is there any giveaway that a UFO is on a mission that involves landing vs. just scanning around?

[Meridian]

1.
- a UFO can outrun your interceptor if it has a higher maximum speed than the interceptor
- approach speed in OXC is always the same
- approach speed in OXCE can be affected by the bravery of the pilots (-50% to +100%); hunter-killer UFOs in OXCE always approach their target at max approach speed
- UFO escape/disengage countdown depends on the UFO, on RNG and on the difficulty level
- disengage speed in OXC is always the same
- disengage speed in OXCE can be affected by the interceptor's acceleration stat (if the interceptor is piloted)

2.
- in mods, there is no way to guess
- in vanilla:
- Mediums always land
- Retaliation never lands
- Very Small almost never lands
- everything else almost always lands

[Zesty]

Thank you, very helpful!

[The Reaver of Darkness]

When a UFO decides to run away is based on its escape timer, and it rolls a value anywhere from the internal escape timer to some additional amount below it. On higher difficulties, there is an additional reduction to the escape timer depending on the difficulty. This means that the lower a UFO's escape timer, the more random its time to flee will be, and the more it will vary by difficulty.

In vanilla, small and very small UFOs will flee fairly quickly, but anything larger typically stays for the whole fight.



You can use the hyper wave decoder to make a better estimate about whether a UFO will land or not. This works in both vanilla and mods; you simply have to watch what a ship does in a given mission and try to find a pattern. It is rarely guaranteed, however, but some missions land a lot while others pretty much never land.

A UFO's specific mission, region, and wave number determine its exact flight pattern (randomized by choosing a random waypoint from a specified list), however mods are able to make multiple different missions with the same name.