Driving in Leadwerks 4.5

[Marcousik]

It is possible to drive in Le 4.5, but first you have to build a little car system, here is what was made until now:

 

I will expose now how far I am with programming this, so that other members can maybe work on this:

This is the structure I created:

 

In blue are the most important children to make the car:

- the "wheels" - are fake decorativ wheels to make the car looks like a car (not so important)

- The "axe" children are pivots that will build through the script the suspensions. (slider joint)

- The "direction" children are pivots that will build the steering system (hinge joint)

- The "roue" children are cylinder CSG to make the tires. (hinge joint)

Here is the script added on the "jeeplight" main object: that is CSG box with invisible material.

 

Okay let see the script:

 

------------------------------------------------------     Script variables properties:

Script.CarMass=200--int "Car Mass"        
Script.TireMass=10--int "Tire Mass"        
Script.SpeedMax=1000--int "Max speed"    
Script.Amort=0.3--float "Amort, long"    
Script.Force=2000--int "Amort, force"    
Script.Rayon=0.5--float "Roue, Rayon"
Script.Epaiss=1--float "Pneus, Épaisseur"
Script.SeeWheels = false --bool "Voir Roues"       -------  not so important
Script.traction=4--int "traction 2/4"    

 

-------------------------------------------------------
function Script:Start()

-- Catch the children:
self.Axes={}
    self.Axes[0]=self.entity:FindChild("AxeAvG")
    self.Axes[1]=self.entity:FindChild("AxeAvD")
    self.Axes[2]=self.entity:FindChild("AxeArG")
    self.Axes[3]=self.entity:FindChild("AxeArD")

self.Directions={}
    self.Directions[0]=self.entity:FindChild("DirectionAvG")
    self.Directions[1]=self.entity:FindChild("DirectionAvD")

self.Tires={}                                                                        -- "real" tires - invisible cylinders
    self.Tires[0]=self.entity:FindChild("RoueAvG")
    self.Tires[1]=self.entity:FindChild("RoueAvD")
    self.Tires[2]=self.entity:FindChild("RoueArG")
    self.Tires[3]=self.entity:FindChild("RoueArD")

self.Wheels={}                                                                   --- fake wheels "decorativ" not so important
    self.Wheels[0]=self.entity:FindChild("WheelAvG")
    self.Wheels[1]=self.entity:FindChild("WheelAvD")
    self.Wheels[2]=self.entity:FindChild("WheelArG")
    self.Wheels[3]=self.entity:FindChild("WheelArD")

    for n=0,3 do
        self.Wheels[n]:SetParent(self.entity) 
    end

self.PosWheels={}
    self.PosWheels[0]=self.Wheels[0]:GetPosition()
    self.PosWheels[1]=self.Wheels[1]:GetPosition()
    self.PosWheels[2]=self.Wheels[2]:GetPosition()
    self.PosWheels[3]=self.Wheels[3]:GetPosition()

    for n=0,3 do
        self.Tires[n]:SetScale(self.Epaiss,self.Rayon*2,self.Rayon*2) 
        self.Tires[n]:SetFriction(10,10)
    end

-- Joints:
self.Volants={}
self.Rouages={}
self.Amortisseurs={}

self.currspeed=0
self.entity:SetMass(self.CarMass)

-- Construit les amortisseurs: /  -------------------------------------     suspensions
local n
local pos
    for n=0,3 do
        pos=self.Axes[n]:GetPosition(true)
        self.Axes[n]:SetMass(self.TireMass)
        self.Amortisseurs[n]=Joint:Slider(pos.x, pos.y, pos.z, 0,1,0, self.Axes[n], self.entity)

        self.Amortisseurs[n]:EnableLimits()
        self.Amortisseurs[n]:SetLimits(-0.1/2,0.1/2)

        self.Amortisseurs[n]:SetTargetAngle(-self.Amort)    --at the middle if 0
        self.Amortisseurs[n]:SetMotorSpeed(1)    -- 1 m/s -- vitesse de la pompe
        self.Amortisseurs[n]:SetStrength(self.Force)    --defatul is 1000
        self.Amortisseurs[n]:EnableMotor()    
--        self.Amortisseurs[n]:SetSpring(50000)

    end

-- Double la force des amortisseurs arrieres /    ---------------------  make the backward suspensions with 2* forces
self.Amortisseurs[2]:SetStrength(self.Force*2)
self.Amortisseurs[3]:SetStrength(self.Force*2)
self.Amortisseurs[2]:SetMotorSpeed(2)
self.Amortisseurs[3]:SetMotorSpeed(2)

-- Volant:                    -   ------------------------------------------steering: Forward
    for n=0,1 do
        pos=self.Directions[n]:GetPosition(true)
        self.Directions[n]:SetMass(self.TireMass)

        self.Volants[n]=Joint:Hinge(pos.x, pos.y, pos.z, 0,1,0, self.Directions[n], self.Axes[n])
        self.Volants[n]:SetAngle(0)
        self.Volants[n]:EnableLimits() 
        self.Volants[n]:SetLimits(-30,30)
        self.Volants[n]:SetMotorSpeed(200)
        self.Volants[n]:EnableMotor() 
    end

-- On attache les roues:    /--------------------------------------- attach the tires
    for n=0,3 do
        pos=self.Tires[n]:GetPosition(true)
        self.Tires[n]:SetMass(self.TireMass)
        if n<2 then
        self.Rouages[n]=Joint:Hinge(pos.x, pos.y, pos.z, 1,0,0, self.Tires[n], self.Directions[n])
        else
        self.Rouages[n]=Joint:Hinge(pos.x, pos.y, pos.z, 1,0,0, self.Tires[n], self.Axes[n])
        end    
        
    end

end

-------------------------------------

function Script:UpdatePhysics()

if self.MyCar==1 and InCar>0 then         ---   these ar my own variables to let the player ingame use the car (not so important for now)

    
-- Traite la direction:                               ---   --------------------manage the steering
    local direction=self.Volants[0]:GetAngle()

    if window:KeyDown(Key.Left) then
        direction=direction-5
    elseif window:KeyDown(Key.Right) then
        direction=direction+5
    elseif window:KeyDown(Key.Left)==false and window:KeyDown(Key.Right)== false then 
        if Math:Round(direction)>0 then direction=direction-5
        elseif Math:Round(direction)<0 then direction=direction+5
        end
    end
    self.Volants[0]:SetAngle(direction)
    self.Volants[1]:SetAngle(direction)

-- Traite l'acceleration:---------------------------------------------------------- manage acceleration

local Gas=0
        if window:KeyDown(Key.Up) then
            Gas=1
            self.currspeed = self.currspeed + 10
            if self.currspeed>self.SpeedMax then
                self.currspeed=self.SpeedMax
            end
        
        elseif window:KeyDown(Key.Down) then
            Gas=1
            self.currspeed = self.currspeed - 10
            if self.currspeed<-self.SpeedMax then
                self.currspeed=-self.SpeedMax
            end
        end

        if Gas==0 then  self.currspeed=0
            for n=0,self.traction-1 do
            self.Rouages[n]:DisableMotor()
            end
        else
            for n=0,self.traction-1 do
            if self.Rouages[n]:MotorEnabled()==false then self.Rouages[n]:EnableMotor() end
            self.Rouages[n]:SetTargetAngle(self.Rouages[n]:GetAngle()+500)

            self.Rouages[n]:SetMotorSpeed(self.currspeed)
            end
        end

--limite la velocite angulaire        /   ----------------------This limits the "twisting" of the car while fast driving, it is not enough but better
    self.entity:SetOmega(0,0,0)

-- fake wheels update:
    
        self.Wheels[0]:SetMatrix(self.Tires[0]:GetMatrix())
        self.Wheels[1]:SetMatrix(self.Tires[1]:GetMatrix())
        self.Wheels[2]:SetMatrix(self.Tires[2]:GetMatrix())
        self.Wheels[3]:SetMatrix(self.Tires[3]:GetMatrix())

        self.Wheels[0]:SetPosition(self.PosWheels[0])
        self.Wheels[1]:SetPosition(self.PosWheels[1])
        self.Wheels[2]:SetPosition(self.PosWheels[2])
        self.Wheels[3]:SetPosition(self.PosWheels[3])
end

 

---------------------------------

 

On the posted image above the used properties can be read.

Most important are the force and the car mass parameters.

Here is what I could test:

- I could make out of this a rapid car but I encounter the problem that the car is bouncing in chaos on the road as the acting forces on the   chassis are big big.

- Augmnenting the mass makes the joints too weak.

- I get the idea that the car actually doesn't have 2 axles as it maybe should have.

 The 2 wheels forward are not bound through an axle just like the backwards too.

- As the car drives, the back of the chassis tends to  sink to the floor/terrain, that's why I doubled the suspensions forces of the backwards wheels

 

There much more to test in this.

(sorry if my english is not so english ?)