Game scale in Open TTD (+poss. feature req.)

[Simons Mith]

New here. Hi all. Question on game scale follows:

According to the Wiki, a square in OpenTTD is about 429 miles across (686 km). This arises from a train moving at a constant 100 mph being able to cover 5.6 squares per day. It means England to scale would be about two squares long, or, at a stretch, a 2x2 triangle. So, space for one building, one road tile and one rail tile. No space for stations or depots, unfortunately.

But that's not the only way to look at the game scale. In play, a typical rail layout looks like an aerial view from a height of about 3-6,000 feet. Check Google for a number of comparable images of real railways.

If you take that as the game scale instead, you get a different answer to the size of a square. Will someone confirm my calculations and assumptions here, please, because I want to confirm I've got my sums right before I put them on the Wiki? (Er, shall I put it on the Wiki? Or should I not?) Thanks.

I did find a thread from 2007 giving a ballpark of 25 metres per square, which roughly gibes with what I've worked out below. (Subject 'world map', Thu May 10, 2007, 9:10pm) BTW is the length-of-day patch ThunderAI refers at the end of that thread available anywhere? Adjustable day length is in the Requested features section of the Wiki at 50% complete. Scalable vehicle speed, I haven't spotted anywhere.

Anyway:

A train moving at 100 mph is moving at 160 kph or 44.44 m/s.

100 mph is also equal to 5.6 squares per day.

A 'day' in OpenTTD is 2.36 seconds.

So 5.6 squares per day is 2.37 squares per second.

Therefore 44.44 m/s is the same speed as 2.37 squares per second, which means a square is 18.73 metres.

On my screen, a square is pretty much exactly 1 cm along a side, which means the aerial view is taken from an altitude of 1873 metres which is 6145 feet.

(Perspective rendering; to get the apparent size of an object, divide its true size by the distance to it, hence a building 25 metres on a side viewed from 2 km away will appear to be 25/2000 = 0.0125 metres on a side which is 12.5 mm.)

If this were true, though, the width of the tracks should appear to be about 1 mm, and they're somewhat larger. If I use the width of a track as my yardstick instead, I get an apparent altitude of 1,000-1333 metres, 3280-4374 feet. You'll get different answers again if you use the size of a bus as your yardstick, or the size of a building, or the width of a road, but answers in the 3-6,000 feet ballpark seem about right to me. Basing it on vehicle speed gives an altitude value which I feel is a bit on the high side.

If you assumed the 'true altitude' of the viewpoint was lower than my 1873 metres, then all vehicles are drawn going too slowly for their supposed game speed. So my possible feature request is: Could we have scaling factors for vehicle speed, and possibly day duration in 'seconds per day', AI ticks per day and payment rates per square as configurable factors? I like playing about with the earlier train models - and even 80 mph seems a bit chuggy when the game is drawing it as if it was 43 mph or so. If I could set a speed multiplier of 1.873, then I'd get 1 square = 10 metres and 80 mph = 8.4 squares/day and the game would feel a lot zippier. If I could scale the payment rates too (and I believe that bit at least can already be done), then I could make my alteration without distorting the game economy. I don't tend to worry much about what the AI is doing, so configurable AI ticks are optional as far as I'm concerned, but if that bit can be adjusted easily I bet there are people who would like it done.

I'm assuming that a 'day' is consistently 2.36 seconds. Is this correct, or is that a value that can vary from one computer to another? Second, my measurement relies on my particular screen resolution, which will vary for other people. So, question: how big is one square on your screen (at maximum zoom) in your preferred resolution? If anyone cares to give me a few measurements I'm idly curious what the typical scale of the game is. e.g. If the typical square size on-screen is 7.5mm, then that means your 'viewing altitude' is 2497 metres.

(viewing altitude in metres = 1873/length of the edge of a square in cm)

[peter1138]

It is a game. Please ignore scale.

A game day happens every 74 game ticks. A game tick happens every 30ms, unless the CPU cannot cope. So a game day is 2.22 seconds.

[SpComb]

Or rather, there's more than one scale used, and they're related together in arbitrary ways.

In terms of the time scale, there's two fundamental units used - ticks (30ms) and days (74 ticks). Everything happening in the game is timed using one of these two.

If you're talking about daylength, then you're talking about changing the relation between game-time in days and real-world time in ticks, and yes, that's possible - but there's more side-effects there than "simply" adjusting any payment rates will "fix".

Graphics scale is whatever the artists choose to draw.

Once you start talking about distance scale and vehicle movement speeds, you're opening up a whole can of hurt - I'm not going to go there, not familiar enough with it.

Pixel scale on your monitor is whatever the manufacturer chooses to use - I doubt OpenTTD takes your monitor's DPI into account, so it's completely irrelevant.

[LurkerL]

The problem encountered in other games is that it opens up a whole can of worms regarding the fineness of details throughout the whole game and the whole slippery slope/where do you stop thing. Arbitrarily sized land squares should be a pretty big signal that actual physical distance is not material to gameplay . I think the current system is fine...

[Elukka]

The most likely way the scale was determined was Chris Sawyer doing whatever looked good.