Vehicle physics rework

[The_Lone_Badger]

I want it to be more realistic. So if you’re driving at 200 mph then yes, that bush will probably cause you to spin like a washing machine working overtime, with no hope of stopping until you’re smeared across every tree in the vicinity.

Not if your mass is a sufficient multiple of its mass and the impulse applied to your vehicle ends up being quite small.

[Robert_Boettcher]

if physics were correct, a steamroll should not skid at all and instead drive almost stubbornly im a straight line, stopped doing so only by fumbles, walls and damage to the front roll.

[vidarsk]

Correct, it would continue in a straight line. However I imagine at that speed it would have no grip at all and thus spin like crazy from the slightest impulse.

[system]

How about top speed being limited to 40% while going backwards? If a sportscar has a top speed of 200mph doesn’t mean that can hit the same speed in reverse.

Also, I may be wrong but as of now vehicles can trigger landmines when you drive on it, doesn’t matter which part “touches” the landmine.
Shouldn’t landmines trigger exclusively from wheels or other parts that touch the ground?

[kevin.granade]

I updated the trap interaction code to only trigger traps with the wheels a while back.

[vidarsk]

[quote=“Vareruma, post:8, topic:8465”]How about top speed being limited to 40% while going backwards? If a sportscar has a top speed of 200mph doesn’t mean that can hit the same speed in reverse.

Also, I may be wrong but as of now vehicles can trigger landmines when you drive on it, doesn’t matter which part “touches” the landmine.
Shouldn’t landmines trigger exclusively from wheels or other parts that touch the ground?[/quote]

When going backwards, cataclysm 0.B limits it to 25% top speed and 60% acceleration. I’ll keep the 60% acceleration (engine power) limit, and top speed in reverse will be calculated based on that. Normally the gear box would be the main limit to reverse speed, so since gear boxes are not in the game (yet), reverse speed will probably be pretty high. I don’t have a problem with that, some cars can drive really fast in reverse. The 60% value can easily be lowered if people disagree with me.

[grisamentum]

What about electrical systems? From what I recall the entire engine/alternator/battery situation was coded by someone who had no clue how cars actually work.

[vidarsk]

What about electrical systems? From what I recall the entire engine/alternator/battery situation was coded by someone who had no clue how cars actually work.

Oh, do you have any examples of what isn’t working?

[KA101]

Just popping in to say that I’ve done 40 MPH in reverse, manual transmission, was a Mazda of some sort. Just learning how to drive at the time and had a wide open lot.

Still scared my mother half to death though.

[Coolthulhu]

Oh, do you have any examples of what isn’t working?

It’s not that it isn’t working, just that it is a simplification.

For one, I’m pretty sure alternators aren’t just an on/off thing.
In current system, you can’t disengage the alternator and you can’t make it take more power when using it as a generator. Their load on the engine is totally separate from the one that powers the wheels (ie. having a truck alternator won’t slow down your car, except for the weight) and is also relatively minor.

Batteries are also simplified in that they charge sequentially (in the order in which they were installed), have 100% efficient charging/discharging and don’t lose power for idling. This means that when you’re using electric engines, the best choice when installing batteries is installing as many as you can (except on the bumper). Real life pure electric car batteries are heavy as hell.
They also have no performance degradation from old age, but that’s actually a good thing - aging batteries you need to constantly dispose of/reinstall would be annoying and very bad design.

[vidarsk]

[quote=“Coolthulhu, post:14, topic:8465”]It’s not that it isn’t working, just that it is a simplification.

For one, I’m pretty sure alternators aren’t just an on/off thing.
In current system, you can’t disengage the alternator and you can’t make it take more power when using it as a generator. Their load on the engine is totally separate from the one that powers the wheels (ie. having a truck alternator won’t slow down your car, except for the weight) and is also relatively minor.

Batteries are also simplified in that they charge sequentially (in the order in which they were installed), have 100% efficient charging/discharging and don’t lose power for idling. This means that when you’re using electric engines, the best choice when installing batteries is installing as many as you can (except on the bumper). Real life pure electric car batteries are heavy as hell.
They also have no performance degradation from old age, but that’s actually a good thing - aging batteries you need to constantly dispose of/reinstall would be annoying and very bad design.[/quote]

While it would be great if everything was simulated perfectly, I have to choose what to spend time on. I’d rather fix collisions than work on batteries. While working on basic vehicle physics I’ve done some changes to power and alternators, but everything is still simplified.

[jokermatt999]

I think that simplification is a good thing. It avoids tedium. Keep working on the physics rewrite though; I’m looking forward to it.

I’d like to implement something like tank/construction treads that have low speed but are harder to stop via collision. Would this rewrite make that easier?

[ramesesniblet]

I think that simplification is a good thing. It avoids tedium.

Couldn’t agree more.

[Slax]

All of this sounds incredibly exciting. Deeelicious!
Wheel grip/traction being the top scorer in my eyes, I have to wonder, will suspension be introduced as well? Let’s say you’re riding a simple bike (stiff frame, no proper suspension) on dirt/grass. That’s a pretty tough ordeal if you’re in full combat gear + wearing a lot of storage items. Well, at least it should be. Get a mountain bike with some suspension and you’ll likely be able to get up to a more… comfortable speed.

Rambling. Thinking out loud. Still, I’d like some more complexity for traction stuff.

[Llamageddon]

Something that I personally would appreciate a lot would be realistic aerodynamics limiting vehicle speed, and a “cruise speed”(optimal distance/fuel speed) based on that and friction.

[iceball3]

[quote=“Llamageddon, post:19, topic:8465”]Something that I personally would appreciate a lot would be realistic aerodynamics limiting vehicle speed, and a “cruise speed”(optimal distance/fuel speed) based on that and friction.[/quote]I doubt that aerodynamics have any place in the vehicle system as if is. As it is, the frames do not have any true shape. As it is, all cars would “aerodynamically” behave like giant lego scooters.

[MorsTactica]

Sorry to totally necro this but alternators actually can and do effect the performance of engines. Same with A/C compressors. They’re all hooked up to the main engine belt witch draws its power from the engine directly via the torque of the pistons. If you have a 100-300 HP car go start it up then turn the A/C on full blast while idling in park. Your RPMs will drop 50-200 below standard idle. This is why there are different types of alternators, a V-twin motorcycle engine would stall out if it tried to turn the alternator on a backhoe. The reasoning behind this is that heavier duty alternators have more powerful magnets and larger resistance. The capacitor doesn’t really matter too much in regards to the engine performance as it’s just there to help through power need spikes and drops, kinda like a mini-battery. Alternators also effect the engine more when under large power draw.

A diagram for you visual learners:

All that said, using a normal truck alternator you don’t see it effecting a V-12 more than an MPH or two even under heavy draw, but it would likely drop a inline V4 10-15 MPH top speed, or maybe more.

At the end of the day I thing the current system (O.C Cooper stable) of alternators is a great balance of realism and play.

[Chase]

That diagram makes me wonder, why don’t we have starters? It would be far better to have a bad starter then a bad engine that needs replacing in a car. Also could have different sizes to start different HP engines. Light V-Twin and below, Medium L4 to V6, Heavy up to V12+. Bigger starter takes more power to start the car, assuming the starter can start it at all. But maybe I am just thinking aloud.

[MorsTactica]

That diagram makes me wonder, why don’t we have starters? It would be far better to have a bad starter then a bad engine that needs replacing in a car. Also could have different sizes to start different HP engines. Light V-Twin and below, Medium L4 to V6, Heavy up to V12+. Bigger starter takes more power to start the car, assuming the starter can start it at all. But maybe I am just thinking aloud.

Sure, but then why not include a radiator too? And the AC as a system? And the dome lights as at item?

Personally, I’d love it. But I’m a gearhead. Most people aren’t even sure what a starter is, it’d just be tedious part swapping for them.

[vultures]

That’s the thing with levels of realism. Not so long ago, I was thinking about axle F and R, because of driving back and forth through the wastes whilst doin’ 50 or more mph; no matter how good of a driver you are, off-road attempts backfire on the driveshaft and suspensions. So I had suggestions, but…

I imagine those abandoned, dented vehicles are a nightmare to run. A quarterpanel just hanging from the welds has a serious impact on overall speed, maneuverability and can be heard of from blocks and blocks away. Misshapen frames should steer the vehicle off track or make it highly unstable, slow and less responsive; missing ones should at least block the controls once in a while, whereas in real life those controls would get wasted in a matter of minutes.

As long as there isn’t a copious ammount of detail on the account of vehicle physics and a method of displaying these information to an in-game character with high enough Mecha skill, we can’t have this three-dimensional picture of CataDDA driving:

Preset – Customization – Performance

As for now, driving and enhancing the in-game rig is just a lot of fun, which is great regarding the ammount work put in for it to function this way. Even when it’s WIP and doesn’t make a lost of RL sense, at least the ride is great.