Add Vehicle Towing

[TheCandianVendingMachine]

When merged this pull request will:

• Implements 2.06's setTowParent
• Adds the ability to attach a rope to a car/tank and tow a given carx vehicle
• Moves ACE_ropeX from ace_fastrope to ace_common
• Adds 2 shorter ropes

Requires ARMA version 2.06. Any vehicle with simulation TankX or CarX can tow any vehicle with simulation CarX - this is an engine limitation and I don't really have any way to tell the user that is the case: any suggestions?

In Action: https://youtu.be/hSGIu9_rrCg

[severgun]

any suggestions?

Attach Tow Rope action throw hint / CBA_fnc_notify that vehicle can not be towed (due to game limitations) if vehicle simulation is not CarX.

[veteran29]

Damn, I wanted to write something very similar this weekend ;-D

Nice one!

[dedmen]

Btw with 2.06 you can now also make custom rope models/textures.
Though I think the normal rope is appropriate here.

The problem that you have to use the brakes to "loosen" the brakes of the towed vehicle is weird ish.
I had to implement a special hacky way to start the vehicles physx simulation by force-rotating the front wheels.

I think the issue here might be that the rope actually stops and pulls back the heavy truck (in your video), so at the point where you affect force on the towed vehicle, you instantly stop.
The engine thing only works if the front vehicle is accelerating, not when its stopped.

One possible thing could be to use addForce or setVelocity to push the towed vehicle slightly.
But the big problem there is finding out when to do it and how hard to do it.

In my testing I always attached rope first and then setTowParent, not 100% sure if its relevant though

myRope = ropeCreate [f1_1, [0,-2,-1], f3_1, [0,1,-1], 10];
f3_1 setTowParent f1_1;

[dedmen]

Actually, I just retested vehicle towing in our internal build, the brake loosening doesn't happen at all.
Something is broken.

Nvm, I was stoop and didn't call setTowParent 🤦

Nvm I still did a huge fuckup.
I do a linear interpolate using the speed delta between towing and towed vehicle to see how fast to turn the wheels.

in, inMin, inMxa, outMin, outMax
Interpolativ(mySpeed - parentSpeed, 0.1f, 10.f, 0.01f, 0.2f)

As you can see I fucked that up, parentSpeed is usually faster than mySpeed so you always end up with a negative here 🤦

[dedmen]

Okey I fixed my interpolation and added a second factor.
If the rope is stretched more than 110%, it will force turn the wheels to "unstick" the vehicle, even if delta speed is low.
That should also help a bit when you don't gain enough speed to create high enough wheel torque for the towed vehicle.

Requires ARMA version 2.06. Any vehicle with simulation TankX or CarX can tow any vehicle with simulation CarX

TankX can also be towed, but in my tests most ropes were insufficient for the mass and just ripped.

[dedmen]

Does that mean tanks and others with similar mass can't be towed by a single vehicle anymore ?

I don't understand the question, what do you mean by "anymore"? This is a new feature

[TheCandianVendingMachine]

TankX can also be towed, but in my tests most ropes were insufficient for the mass and just ripped.

I just got my info from the Biki page. It explicitly says that TankX can't be towed at all

[dedmen]

Wiki is outdated then

[severgun]

TankX can also be towed, but in my tests most ropes were insufficient for the mass and just ripped.
What defines rope strength and can it be increased?

[dedmen]

What defines rope strength and can it be increased?

You can make custom ropes that stretch less. If a rope stretches too far, it breaks.

class CfgVehicles {
	
	class Rope;
	class RopeDedmen : Rope {
		maxRelLenght = 1.1;
		maxExtraLenght = 20;
		springFactor = 1;
		segmentType = "RopeSegmentDedmen";	
        torqueFactor = 0.5;
		dampingFactor[] = {10,10,10};
	}
}

maxRelLenght -> max stretch before break
maxExtraLenght -> max stretch before break
springFactor -> how much it stretches

[Drofseh]

STR_ACE_logistics_rope_descriptionShort should be modified to indicate the ropes can be used for towing.

[veteran29]

LGTM

[654wak654]

Not a merge blocker but some missing features I noticed while testing:

• Ability to remove tow rope from the towing vehicle's side.
• Some way to block vehicles from getting towed (could be based on vehicle lock).
• Documentation (Doesn't need much).
• Handle either vehicle being deleted. Looks like the engine already handles them getting destroyed, so this might be @dedmen territory. The issue is that one vehicle being deleted leaves the rope & helper object behind. Both being deleted leaves just the helper object behind. Attempting to get your rope back using it causes the following error:

 6:47:49 Error in expression <unit", "_parent", "_child"];
;

_parent removeEventHandler ["RopeBreak", _parent>
 6:47:49   Error position: <removeEventHandler ["RopeBreak", _parent>
 6:47:49   Error Type Any, expected Number
 6:47:49 File z\ace\addons\towing\functions\fnc_detach.sqf..., line 21

[jonpas]

I would merge this now, but that script error is no good, we should cleanup helper/rope objects on vehicle deletion.

[TheCandianVendingMachine]

I would merge this now, but that script error is no good, we should cleanup helper/rope objects on vehicle deletion.

probably fixed

[dedmen]

We won't add handling for vehicle deletion on our side.
But deleted EH will fire before the vehicle goes away so that should be sufficient

[bux]

Got this error after untowing and deleting a vehicle

16:01:31 Error in expression <unit", "_parent", "_child"];
;

_parent removeEventHandler ["RopeBreak", _parent>
16:01:31   Error position: <removeEventHandler ["RopeBreak", _parent>
16:01:31   Error Type Any, expected Number
16:01:31 File z\ace\addons\towing\functions\fnc_detach.sqf..., line 21
16:01:31 Error in expression <"ace_towing_parent", objNull];

_parent removeEventHandler ["Deleted", _hook get>
16:01:31   Error position: <removeEventHandler ["Deleted", _hook get>
16:01:31   Error Type Any, expected Number

I pulled the branch today, after the fix. Seems to still happen.

[bux]

Is it possible to make some vehicles tow "heavier" vehicles? It's currently not possible for the recovery vehicle Nemmera (built on the Merkava Mk3 chassis) to tow e.g. the AAF Leopard.

[TheCandianVendingMachine]

Is it possible to make some vehicles tow "heavier" vehicles? It's currently not possible for the recovery vehicle Nemmera (built on the Merkava Mk3 chassis) to tow e.g. the AAF Leopard.

I fixed the deleting issue finally: was a stupid reason, I forgot that the event handlers would still exist after you detach.

It's on the engine to make vehicles be able to tow other vehicles - as far as I know it has to do with the weight of the vehicles, and manually adjusting weights via script seems like a good way to cause issues