Tips, Tricks and Newb Questions: Reborn!

is by the ceiling exactly?, once i think i had them enabled, went to an apartament tower, it was kind of deserted from usually and when i went back to ground level, at full horde of almost nearly dead zombies caught me by surprise, never again played again with z-levels on

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Has NPC training been reworked recently? I asked a friendly NPC to train me but only improved the skill by 3%. I get that NPC training was kind of broken before but it looks near useless in the current state (Build 9543).

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So…i have 3 mature chicken and 2 chick…i put it on chicken coop. my question is, did my chick is going to be grow and did the mature one lay an egg?? Is that mistaken i tame a chicken? Because i tame it all so it can be controlled lol

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Sorry my english are bad lol…i mean how long chicken grow and did chicken produce an egg?

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You pretty much experimentally determined the correct answer, but you got some of the cause and effects wrong.

Each engine in the game produces some amount of motive power, and consumes some amount of thermal energy to do so. Bigger engines produce and consume more power. The ratio of motive power to thermal energy is the engine’s efficiency. Electric motors are very efficient, steam engines about half that, diesels a little less efficient than steam, gasoline combustion somewhat less than diesels, and gas turbines are terrible.

Each fuel type produces some amount of thermal energy when burned: diesel is a little more energetic than gas, both are better than methanol which is better than lamp oil, and charcoal is the worst by a long shot.

Each second when a vehicle moves, it is slowed down by rolling resistance and air drag (or air drag and water drag for boats). It then accelerates back to cruise speed. The ratio of the amount it accelerates to the amount it can accelerate at the speed is strain, and strain is multiplied by the engine’s thermal consumption to calculate how much fuel needs to be burnt this second. Also, a vehicle’s top speed occurs when its acceleration and slowdown are equal to each other - the vehicle can’t accelerate to any faster than its top speed.

Air drag is proportional to the square of the vehicle’s speed, but each vehicle has it’s own coefficient of drag (CoD) calculated from the design. Generally, long, thin vehicles have low CoD and things like turrets, exposed passengers, and aisles increase CoD.

Water drag is also proportional to the square of speed, but water is 1000 times as dense as air, so the effects of water drag are much greater than for air drag. The CoD for water is determined mostly by the percentage of your vehicle’s tiles that have boat hulls in them and the vehicles draft. Your vehicle’s draft (how much of it is underwater, basically) increases with vehicle weight and decreases as the length and width of your vehicle increases, as well as when more of your vehicle has boat hulls.

Rolling resistance is proportional the vehicle’s speed and weight, with some factors for wheel design. Generally, harder and narrower tires produce lower rolling resistance - the ultimate example being the railroad wheel, which has a really low rolling resistance - but the better a tire’s rolling resistance on pavement or wheels, the worse it is off-road (or off-rail, for railroad wheels).

A vehicle’s off-road performance depends on the wheel surface area and wheel design relative to the vehicle’s weight and the off-road terrain. The more wheels you have, and the wider those wheels are, the more wheel surface area you have and the better your off-road performance. The heavier your vehicle is, the worst the performance. The off-road performance reduces vehicle acceleration and speed to some percentage between 0% (terrible off-road performance) and 100% (amazing off-road performance).

So, from your observations:

  1. Light vehicles have lower rolling resistance, so they slow down less at any given speed than heavier vehicles. That means there’s less strain on the engines, so less fuel consumption.
  2. Engine size is really complicated, as you note. Smaller engines consume less fuel for the same amount of strain, but a larger engine can have more acceleration and less strain for a given vehicle design. But large engines also weigh more. On a tank, the difference between the weight of a V6 and V8 isn’t very much compared to the overall weight. On a roadster, it’s a bit more noticeable.
  3. Aerodynamics is generally a huge factor, especially when you’re going fast on roads. At low speed, rolling resistance matters more.
  4. Wheels affect rolling resistance and off-road performance, but off-road performance is relative to top speed. If you spend a lot of time off-road or have a very heavy vehicle, get treads or multiple off-road tires. Bicycles are often light enough to get good off-road performance even with standard tires.
  5. Speed matters, but it’s speed relative to the vehicle’s top speed. A pimped out roadster that can do 300 kph is probably feeling very little strain, cruising at 130 kph. A mobile fortress that has a hard time reaching 90 kph is going to be under a lot of strain at 80 kph.

The current CDDA vehicle model uses a decent but imperfect approximation of real world physics. Doing things that would reduce fuel consumption in the real world should generally be effective in CDDA: stay at a constant speed that isn’t too fast, use an appropriately sized engine for your needs, don’t go off-road unless you’re designed to, be aerodynamic. Sadly, the requirements of running a mobile fortress in the post-Cataclysm threat environment makes doing that fairly hard, and your typical deathmobile consumes gas like a M1 Abrahms does - 1L per mile or so.


If I’m reading the .json right, chickens lay eggs every 5 days? 5 hours? Not sure what the unit of measure is there. Eggs take 7 days to hatch and have a 70% chance to produce a chick. Chicks take 14 days to grow into chickens. I hope this helps.

edit: By ‘hatch’ I mean rot. Rotting is how all the eggs work.


I’m yet to see a non-rotten rottweiler lol


Thanks for the extremely detailed explanation. I’m very tempted of redoing the tests with the new info, as there’s only so much rule of thumb can achieve :laughing:

If you can compile the game, there’s a file in the tests/ directory called vehicle_efficiency.cpp that takes a list of stock vehicles, fills their tanks to 1% of normal, and then simulates driving them until their tank is empty and spits out how many tiles the vehicle moved, and does this for pavement and dirt. It takes a couple of seconds to run. You could create some arbitrary test vehicles in JSON and plug them into the vehicle efficiency tests and see what results you get. It’s going to be a lot faster than doing it by hand.

How to run cdda launcher?? I just download it and dont have an idea how to run it

that weird, you just use the installer, and after that you only have to click the shortcut and it launches automatically, did you download the latest version?

There is a guy give me link from pk rebalance unofficial patch thread here in this forum.
i download it unzip it and there is no launcher inside it

the latest i downloaded was from the author github

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Where can we find medium battery?

Check restaurants. This seems to be the only place I can find them mentioned in json.

Thanks! I need them for the welder.

Ok, nvm…they should show up anywhere batteries show up. Seems to have an equal chance.

_k1 if you’ve got the skills, you can make a mod for your welder to let it accept vehicle and small storage batteries: battery compartment mod. This is what I do most often bc I can never find medium batteries.

Thanks for reminding me the battery compartment mod! I also used to always make that so I can use vehicle batteries.

is normal now for i bike to dont move if you add an alternator?, i remember being able to add an alternator and charge batteries while moving, making one able to change between pedal as a motor an electric motor