If you know it to the last detail, would you mind sharing how fast interceptor approaches to enemy so we don't need to run these visual tests anymore? 😀

In OpenXcom (OXC), the approach speed is 2, a constant.

https://github.com/OpenXcom/OpenXcom/blob/master/src/Geoscape/DogfightState.cpp#L798In OpenXcom Extended (OXCE), the approach speed can be 1, 2, 3 or 4, depending on pilot skills. If there are no pilots, it's just 2.

https://github.com/MeridianOXC/OpenXcom/blob/oxce-plus/src/Geoscape/DogfightState.cpp#L1018You have probably noticed that I didn't mention kilometers or seconds.

That's because (Open)Xcom doesn't use either of those, it's using arbitrary "xcom distance units per xcom time units".

Xcom distance units can be with a little bit of imagination (based on ingame Ufopedia) converted into kilometers.

The conversion rate to 1:8, e.g. 640 xcom distance units = 80 km.

I have even implemented an option to show distance in the Interception window in kilometers:

https://github.com/MeridianOXC/OpenXcom/blob/oxce-plus/src/Geoscape/DogfightState.cpp#L1039Xcom time units cannot be converted into anything "meaningful":

a/ game/geocape time would be zero

b/ real world time depends on user options (not on frame rate)

But again with a little bit of imagination, we can call one "game tick" as one "game second".

OpenXcom made that assumption and that's why you see cannon reload time in OpenXcom as 4 game seconds.

Original Xcom1994 did not make that assumption and that's why you see cannon reload time in the original as 2 game seconds (even though both reload times are the same (4 ticks), they just define a game second differently... as 2 "game ticks").

So for OpenXcom:

- approach speed is 2 xcom distance units per 1 game tick = 2/8 kilometers per 1 openxcom game second (ogs) = 0.25 km/ogs

For original Xcom1994:

- approach speed is 2 xcom distance units per 1 game tick = 2/8 kilometers per 0.5 xcom1994 game seconds (xgs) = 0.5 km/xgs (= 0.25 km/ogs)

Please note that these two results are the same, there is no paradox or contradiction anywhere.