- 1 Introduction
- 2 Properties
- 3 Description
- 3.1 Running cost base (0A) and factor (09)
- 3.2 Cost factor (11)
- 3.3 Realistic acceleration properties (13, 14, 15)
- 3.4 Callbacks (17)
- 3.5 Coefficient of tractive effort (18)
- 3.6 Coefficient of air drag (19)
- 3.7 Refit cost (1A)
- 3.8 Miscellaneous flags (1C)
- 3.9 Long format introduction date (1F)
- 3.10 Sort vehicle list (20)
- 3.11 Visual effect (21)
- 3.12 Custom cargo ageing period (22)
- 4 Example
Defining properties of road vehicles.
|Number||Size||Version||Description||Available for articulated parts|
|08||B||0.6 2.0||Speed in mph*3.2||no|
|09||B||0.6 2.0||Running cost factor||should be zero|
|0A||D||0.6 2.0||Running cost base, see below||should be zero|
|0E||B||0.6 2.0||Sprite ID (FF for new graphics)||yes|
|10||B||0.6 2.0||Cargo type, see CargoTypes
GRFv≤7 For GRF version 7 and below: Type B 'cargo slot'
|11||B||0.6 2.0||Cost factor||should be zero|
|12||B||0.6 2.0||Sound effect: 17/19/1A for regular, 3C/3E for toyland
1.6 Since OpenTTD r27507 also custom sound effects from Action11 are allowed here.
|13||B||1.1 2.0 GRFv≥2||Power in 10 hp, see below||should be zero|
|14||B||1.1 2.0 GRFv≥2||Weight in 1/4 tons, see below||should be zero|
|15||B||0.7 2.0 GRFv≥2||Speed in mph*0.8, see below||no|
|16||D||0.6 2.0 GRFv≥2||Bit mask of cargo types available for refitting (not refittable if 0 or unset), see column 2 (bit values) in CargoTypes||yes|
|17||B||0.6 2.5 GRFv≥6||Callback flags bit mask, see below||yes|
|18||B||1.1 2.5||Coefficient of tractive effort||should be zero|
|19||B||1.1 2.5||Coefficient of air drag||should be zero|
|1A||B||0.6 2.5||Refit cost, using 25% of the purchase price cost base||yes|
|1B||B||0.6 2.5||Retire vehicle early, this many years before the end of phase 2 (see Action0General)||no|
|1C||B||0.6 2.5||Miscellaneous vehicle flags||partly ("tram" should be same as front)|
|1D||W||0.6 2.5||Refittable cargo classes, see train prop. 28||yes|
|1E||W||0.6 2.5||Non-refittable cargo classes, see train prop. 29||yes|
|1F||D||0.6 2.5||Long format introduction date||no|
|20||B*||0.7||Sort the purchase list||no|
|22||W||1.2||Custom cargo ageing period||yes|
|23||B||1.2||Make vehicle shorter, see train property 21||yes|
|24||B n*B||1.2||List of always refittable cargo types, see train property 2C||yes|
|25||B n*B||1.2||List of never refittable cargo types, see train property 2D||yes|
Running cost base (0A) and factor (09)
TTD calculates all costs by multiplying a 48-bit base amount with an 8-bit factor. The base amount is changed according to inflation, whereas the factor remains constant.
For the running costs of road vehicles, the following base amounts are available:
|Type||Value||in little-endian notation|
|Road vehicle running cost base||4C48||48 4C 00 00|
Theoretically, you could use pointers to other base amounts available in TTD, but these are the numbers TTD uses for road vehicles.
Cost factor (11)
The cost factor is a bit-coded value which determines how expensive a vehicle is. The table below gives you some values to use for finding the right price for your vehicles.
Realistic acceleration properties (13, 14, 15)
Using property 15 to set the speed, it is possible to achieve speeds larger than 80 mph (127 km/h), to which property 08 is limited. When setting property 15, always set property 08 as well, so that the vehicle works reasonably well whether realistic acceleration is turned on or off. If property 15 is not set, the value from property 08 is used instead.
For road vehicles, the following callbacks have to be enabled by setting the corresponding bit in property 17 (certain other, not as frequently used callbacks are available without setting a bit here):
|Bit||Value||Variable 0C value||Callback|
|3||8||15||Set refitted capacity|
|4||10||16||Build articulated vehicle|
|5||20||19||show a suffix after the cargo type name|
|6||40||2D||Select color mapping for vehicle|
|7||80||33||Sound effect callbacks|
Bit is the bit you have to set, you do this by adding all the values for all the bits. Variable 0C value is what variable 0C will be set to, for checking it in the VarAction2 for callbacks.
Coefficient of tractive effort (18)
This cofficient sets what fraction of the vehicle weight is equal to the maximum tractive effort. This includes the effect of having some unpowered axles, as well as the coefficient of friction that is available.
For a value of FF, the tractive effort is equal to the vehicle weight, for 80, it is half, and so on. If not set, a default of 4C is used, for a fraction of 0.30, corresponding to Wadh=W and a coefficient of friction of 0.30, which is the value used by the patch before TTDPatch 2.0.1 alpha 19.
Coefficient of air drag (19)
This property sets the air drag coefficient c2 used for the realistic acceleration model, from 01 (no airdrag) to FF (most air drag) in arbitrary units. 00 means to use the default value that depends on the top speed (to simulate the fact that high-speed engines are more streamlined).
The default values are the following:
|top speed (mph/1.6)||<16||16||24||32||48||64||96||128||192||256||...|
For higher speeds, the series is continued in the same manner.
Air drag in Newtons will then be c2*v*v with v in m/s, although it is probably futile to attempt to make c2 a realistic number due to the lack of TTd's consistent scaling. If a vehicle doesn't reach its historical top speed, you might try setting prop. 19 one or two higher than the default above, otherwise it's probably a good idea to leave it at the default.
Refit cost (1A)
Refit cost, using 25% of the purchase price cost base. This property can be overridden by callback 15E.
Miscellaneous flags (1C)
This is a bit mask, with the following bits:
|0||1||Vehicle is a tram/light rail vehicle and requires tram tracks to operate|
|1||2||Uses two company colors|
|2||4||reserved, do not use|
|3||8||reserved, do not use|
|4||10||1.2 Auto-refitting is enabled for refits where callback 15E allows it or prop 1A specifies zero cost.|
|5||20||1.2 Use cargo multiplier for default cargo. See page about vehicle refitting.|
|6||40||1.3 Disable breakdown smoke effect.|
|7||80||1.7 Compose vehicle from multiple sprites.|
Long format introduction date (1F)
Set the vehicle introduction date, in days since the year 0. This takes account of leap years; dividable by 4, but not 100 unless 400. A start date of 1920-01-01 is obtained with a value of 701265 (51 B3 0A 00). This property must be set after property 00 to take effect.
Sort vehicle list (20)
See sort vehicle list for trains for details.
Visual effect (21)
See the equivalent train property for information about the meaning of all bits. There is no default effect for road vehicles, therefore values of 00..0F will show no visual effect. Bit 7 (disable wagon power) currently has no meaning and should be left at 0.
Custom cargo ageing period (22)
See custom cargo ageing period for trains for details.
To be written