Physx problem

[Degman 73]

Hello, I have a problem with Skoda Octavia import from A2. Somewhy a whole body of the car is putting pressure on front wheels.

http://i1269.photobucket.com/albums/jj598/DegmanCro/2014-06-24_00004_zps0f5be57e.jpg (104 kB)

Here's my physx settings (its very similar like to sample):

/// splendid tutorial by RedPhoenix could be found at

/// http://forums.bistudio.com/showthread.php?165390-Tutorial-Creating-Custom-Engine-Gearbox-and-Suspension-Vehicle-configuration

thrustDelay = 0.2; /// initial delay to cause lesser slip when on 1st gear - thrust goes from zero to full in this time

brakeIdleSpeed = 1.78; /// under what speed (in m/s) does the brake apply for a vehicle without thrust

maxSpeed = 200; /// vehicle can go a bit over, but dramatically decreases thrust

fuelCapacity = 50;

wheelCircumference = 2.02; /// diameter of 725

antiRollbarForceCoef = 0.5; /// how strong is the anti-roll bar of vehicle preventing it to lose grip in turns (not any magical stuff, real ARB)

antiRollbarForceLimit = 0.5; /// highest possible force of ARB

antiRollbarSpeedMin = 20; /// the roll bar force gets from zero to full in range of min and max speed

antiRollbarSpeedMax = 80; /// this simulates losing grip at high speed turns

class complexGearbox

{

GearboxRatios[] = {"R1",-3.231,"N",0,"D1",2.462,"D2",1.870,"D3",1.241,"D4",0.970,"D5",0.711};

TransmissionRatios[] = {"High",4.111}; // Optional: defines transmission ratios (for example, High and Low range as commonly found in offroad vehicles)

gearBoxMode = "auto"; //gearbox can be of type: full-auto (only requires 'W' or 'S'), auto (requires shift between drive and reverse), semi-auto, manual

moveOffGear = 1; // defines what gear an automatic or semi-automatic gearbox will move off from stationary in. 1 by default.

driveString = "D"; // string to display in the HUD for forward gears.

neutralString = "N"; // string to display in the HUD for neutral gear.

reverseString = "R"; // string to display in the HUD for reverse gears.

};

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

/// PhysX parameters

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// <Description>: Defines simulation type of the vehicle. PhysX simulation ends with letter "x", "carx", "tankx" ...

// <Type>: string

// <Default>: (required)

simulation = "carx";

// <Description>: Defines how much dampers react to random little bumps on surface. It's only visual effect, doesn't influence drive simulation,

// only taken into account when calculating damper animation.

// <Type>: float

// <Default>: 0.0

dampersBumpCoef = 0.05;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// Differential parameters

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// <Description>: A number of differential types are supported: 4-wheel drive with open differential, 4-wheel drive with limited slip, front-wheel drive

// with open differential, front-wheel drive with limited slip, rear-wheel drive with open differential, rear-wheel drive with limited slip.

// <Type>: string; acceptable values: "all_open", "all_limited", "front_open", "front_limited", "rear_open", "rear_limited"

// <Default>: "all_limited"

differentialType = "front_limited";

// <Description>: Ratio of engine power that goes to front wheels out of total power for 4-wheel drive differentials.

// Choosing a value greater than 0.5 delivers more torque to the front wheels, while choosing a value less than 0.5

// delivers more torque to the rear wheels. This value is ignored for front-wheel drive and rear-wheel drive differentials.

// <Type>: float

// <Default>: 0.5

frontRearSplit = 0.5;

// <Description>: This is the largest possible relative difference between speed of front wheels. It helps to have outside wheels a bit faster

// during the turns, but it prevents the faster wheel to take all the power while sliding. The power is shifted to slower wheel once the value is reached.

// Locked differential has value of 1, the softer is the lock the greater should the value be.

// This value is ignored except for front-wheel drive or four wheel drive with limited slip.

// A good starting value is around 1.3.

// <Type>:

// <Default>:

frontBias = 1.5;

// <Description>: This is similar to frontBias except that it refers to the rear wheels.

// This value is ignored except for rear-wheel drive or four wheel drive with limited slip.

// A good starting value is around 1.3.

// <Type>: float

// <Default>: 1.3

rearBias = 1.3;

// <Description>: This value is similar to the frontBias and rearBias, except that it refers to the sum of the front wheel rotation speeds and the sum

// of the rear wheel rotation speeds.

// This value is ignored except for four wheel drive with limited slip.

// A good starting value is around 1.3.

// <Type>: float

// <Default>: 1.3

centreBias = 1.3;

// <Description>: How fast is engine power distributed to the wheels. Stronger values mean more aggressive drive performance inclining to

// slip a little while changing gears while weaker values are better for comfortable seamless ride.

// <Type>: float

// <Default>: 10.0

clutchStrength = 15.0;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// Engine parameters

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// <Description>: Power of the engine in kW.

// <Type>: float

// <Default>: (required)

enginePower = 96;

// <Description>: This is the maximum rotational speed of the engine expressed in radians per second. It could be calculated from maximum

// engine RPM like this:

// maxOmega = (maxRpm*2*Pi)/60.

// <Type>: float

// <Default>: 600 which is cca 6000 rounds per minute.

maxOmega = 720;

// <Description>: This is the maximum torque that is ever available from the engine. This is expressed in Newton metres.

// <Type>: float

// <Default>: value calculated from enginePower according to http://en.wikipedia.org/wiki/Horsepower#Relationship_with_torque

peakTorque = 350;

// <Description>: These three values describe internal damping of the engine. Bigger values mean greater damping. Clutch disengaged value

// is used while shifting gears, engine interpolates between clutch engaged and full throttle values according to throttle input.

// We tend to use slightly lower clutch engaged values because it allows cars to turn more smoothly.

// Typical values in range (0.25,3). The simulation can become unstable with damping rates of 0.

// <Type>: float, float, float

// <Default>: 0.08, 2.0, 0.35

dampingRateFullThrottle = 0.08;

dampingRateZeroThrottleClutchEngaged = 0.35;

dampingRateZeroThrottleClutchDisengaged = 0.35;

// <Description>: This is a graph of peak torque versus engine rotational speed.

// The x-axis of the curve is the relative engine speed; that is, the engine speed divided by the maximum engine speed. The y-axis of the curve is a

// multiplier in range (0,1) that is used to scale the peak torque. It is good to keep the values in mind while setting changeGearMinEffectivity.

// <Type>: Array[2] where i = number of samples, maximum 8;

// <Default>: {{0.0, 0.8}, {0.33, 1.0}, {1.0, 0.8}}

torqueCurve[] = {{0.000, 0.000}, {0.178, 0.800}, {0.250, 1.0}, {0.461, 0.900}, {0.900, 0.800}, {1.000, 0.300}};

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// Gearbox parameters

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// <Description>: Value of minimal gear effectivity to hold current gear. If there is better gear and effectivity is below this value then change gear.

// <Range>: (0,1)

// <Type>: Array where i = number of gears

// <Default>: 0.95 for every value (Neutral = 0.15 Not sure how important this is but we want to kick out of neutral very quickly)

changeGearMinEffectivity[] = {0.95, 0.15, 0.95, 0.95, 0.95, 0.95, 0.95};

// <Description>: The switch time describes how long it takes (in seconds) for a gear change to be completed. This needs to be set to aggresive shifting

// or it would cause issues while trying to run aggressively (mainly during evading the enemies).

// <Type>: float

// <Default>: 0.01

switchTime = 0.31;

// <Description>: Set the latency time of the gearbox, specified in s.

// This is used to prevent instant shifting after changing gears - there is some power loss during gear change and it could seem that

// previous gear is better for a brief time after shifting.

// <Type>: float

// <Default>: 2.0

latency = 1.0;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// Wheels parameters

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

class Wheels

{

class LF

{

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// General parameters

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// <Description>: Name of the bone, used for wheel and suspension animations.

// <Type>: string

// <Default>: ""

boneName = "wheel_1_1_damper";

// <Description>: If true, wheel is steerable, false - wheel is fixed.

// <Type>: bool

// <Default>: (required)

steering = true;

// <Description>: Defines if wheel is on the right or left side of the vehicle

// <Type>: string

// <Default>: "right"

side = "left";

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// Wheel PX parameters

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// <Description>: Center of the wheel (axis)

// <Type>: memory point

// <Default>: (required)

center = "wheel_1_1_axis";

// <Description>: Point on the outside rim of the tire, used to calculate radius of the wheel (distance between center and boundary).

// <Type>: memory point

// <Default>: (required)

boundary = "wheel_1_1_bound";

// <Description>: This is the weight in kg of wheel including both rim and tyre.

// <Type>: float

// <Default>: 10.0

mass = 20;

// <Description>: This is the wheel's moment of inertia about the rolling axis. Smaller values result in more slips in aggresive driving

// while larger hamper the gain of speed. Good base to start with is this formula:

// MOI = 0.5 * Mass * Radius * Radius

// Some tweaking is needed after the computation, but it is still better than nothing.

// <Type>: float

// <Default>: 0.5 * WheelMass * WheelRadius * WheelRadius

MOI = 3.3;

// <Description>:The damping rate describes the rate at which a freely spinning wheel loses rotational speed.

// Values in range (0.25, 2) seem like sensible values. Experimentation is always a good idea, even outside this range.

// <Type>: float

// <Default>: 0.1

dampingRate = 0.5;

// <Description>: This is the value of the torque applied to the wheel when the brakes are maximally applied. Higher torques will lock the wheel

// quicker when braking, while lower torques will take longer to lock the wheel.

// A value of around 1500 is a good starting point for a vanilla wheel but a google search will reveal typical braking torques. One difficulty is

// that these are often expressed by manufacturers as braking horsepower or in "pounds inches". The values required here are in "Newton metres".

// <Type>: float

// <Default>: 2500

maxBrakeTorque = 2000;

// <Description>: This is the same as the max brake torque except for the handbrake rather than the brake. Typically, for a 4-wheeled car,

// the handbrake is stronger than the brake and is only applied to the rear wheels. A value of 4000 for the rear wheels is a good starting point,

// while a value of 0 is necessary for the front wheels to make sure they do not react to the handbrake.

// <Type>: float

// <Default>: 2*maxBrakeTorque

maxHandBrakeTorque = 0;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// Wheel simulation parameters

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// <Description>: This is the direction of the suspension in the downward direction in the rest configuration of the vehicle. A vector that

// points straight downwards is a good starting point.

// <Type>: Array[3]

// <Default>: {0, -1, 0}

suspTravelDirection[] = {0, -1, 0};

// <Description>: This is the application point of the suspension force.

// <Type>: memory point

// <Default>: center

suspForceAppPointOffset = "wheel_1_1_axis";

// <Description>: This is almost the same as the suspension force app point except for the lateral and longitudinal forces that develop on the tire.

// A good starting point is to duplicate the suspension force application point.

// <Type>: memory point

// <Default>: suspForceAppPointOffset

tireForceAppPointOffset = "wheel_1_1_axis";

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// Suspension parameters

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// <Description>: These values describe the maximum compression and elongation in metres that the spring can support.

// <Type>: float

// <Default>: 0.15

maxCompression = 0.1;

mMaxDroop = 0.15;

// <Description>: This is the mass in kg that is supported by the suspension spring.

// <Type>: float

// <Default>: vehicleMass/numberOfWheels

sprungMass = 350.0;

// <Description>: This is the strength of the suspension spring in Newtons per metre.

// springStrength = naturalFrequency * naturalFrequency * sprungMass

// <Type>: float

// <Default>: sprungMass*5,0*5,0

springStrength = 22600;

// <Description>: This describes the rate at which the spring dissipates the energy stored in the spring.

// Basic equiation for this is

// springDamperRate = dampingRatio * 2 * sqrt(springStrength * sprungMass)

// where dampingRatio = 1 mean critical damping (critically damped pendulum should get back to start point in every swing)

// <Type>: float

// <Default>: 0,4*2*sqrt(springStrength*sprungMass)

springDamperRate = 8680;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// Tire parameters

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// <Description>: Increasing this value will result in the tire attempting to generate more longitudinal force when the tire is slipping.

// Typically, increasing longitudinal stiffness will help the car accelerate and brake. The total tire force available is limited by the

// load on the tire so be aware that increases in this value might have no effect or even come at the expense of reduced lateral force.

// <Type>: float

// <Default>: 10000

longitudinalStiffnessPerUnitGravity = 100000;

// <Description>: These values together describe the lateral stiffness per unit lateral slip (in radians) of the tire.

// <Type>: float, float

// <Default>: 25, 180

latStiffX = 25;

latStiffY = 18000;

// <Description>: These six values describe a graph of friction as a function of longitudinal slip.

// A good starting point for this is a flat graph of friction vs slip with these values:

// frictionVsSlipGraph[0][0]=0.0

// frictionVsSlipGraph[0][1]=1.0

// frictionVsSlipGraph[1][0]=0.5

// frictionVsSlipGraph[1][1]=1.0

// frictionVsSlipGraph[2][0]=1.0

// frictionVsSlipGraph[2][1]=1.0

// <Type>: Array[3][2]

// <Default>: {{0, 1}, {0.5, 1}, {1,1}}

frictionVsSlipGraph[] = {{0, 1}, {0.5, 1}, {1,1}};

};

class LR : LF

{

boneName = "wheel_1_2_damper";

steering = false;

center = "wheel_1_2_axis";

boundary = "wheel_1_2_bound";

suspForceAppPointOffset = "wheel_1_2_axis";

tireForceAppPointOffset = "wheel_1_2_axis";

maxHandBrakeTorque = 3000;

latStiffY = 180;

sprungMass = 190.0;

springStrength = 4750;

springDamperRate = 1760;

};

class RF : LF

{

boneName = "wheel_2_1_damper";

center = "wheel_2_1_axis";

boundary = "wheel_2_1_bound";

suspForceAppPointOffset = "wheel_2_1_axis";

tireForceAppPointOffset = "wheel_2_1_axis";

steering = true;

side = "right";

};

class RR : RF

{

boneName = "wheel_2_2_damper";

steering = false;

center = "wheel_2_2_axis";

boundary = "wheel_2_2_bound";

suspForceAppPointOffset = "wheel_2_2_axis";

tireForceAppPointOffset = "wheel_2_2_axis";

maxHandBrakeTorque = 3000;

latStiffY = 180;

sprungMass = 190.0;

springStrength = 4750;

springDamperRate = 1760;

};

};

[Richards.D 761]

Yep, too easy for a fix here. This is not actually to do with Physx. You need to adjust the weighting of your vehicle in the Geometry LOD so that it has a fairly balanced center of gravity which is no more than half way above the car. The height of the center of gravity will not change this, but play around with the weight until it is more or less centered, depending on how you want it to ride.

[Degman 73]

Ah, I wish that was a solution, but unfortunately it is not. :| I even tried with mass=0, but still I get this weird "gravity bug" - if I should call it like that. No matter what config/model parameters I changed - its always present. I have never experienced such as thing. Also, I did not had similar problems while converting M1151. No idea what to do.

[cleggy 297]

I think RichardsD is right.

Have you noticed the four triangular things in the geometry LOD of the BIS test car?

do you have them in your geometry LOD? If not try them and give them almost the entire mass of the vehicle.

I had the same problem as you and I found by moving the triangular things forward/backwards leveled my vehicle up

in relation to the horizontal. I now have them just above each wheel and I have a level vehicle.

Also the centre of mass of these triangular things (selected by themselves) is the same as the centre of mass of the entire vehicle when everything is selected.

[Richards.D 761]

I guess another possible thing to try would be to ensure that your suspension is not overly compressed in the front, and that the mem points are pretty much equal in distance between the front and back. If you are having trouble, perhaps delete your mem points for the wheels and try copying the ones from the sample car again, perhaps you accidentally flipped them or something.

Richards

[cleggy 297]

perhaps you accidentally flipped them or something.

Actually, that's an interesting point. does an axis have a direction?

A damper goes up AND down so which is the direction of travel?

Sorry, don't think this is too OT, it might be the solution!

[Degman 73]

Yeah, triangles really helps! Vehicle mass is now normaly working. Thanks! :) (...) Now there are other bugs. I know im boring as hell, but I just couldn't find a solution.

a) vehicle is jumping

b) light & dust effects are not in their positions, but they spawn in centre of vehicle (for some reason). I did all config work, as well as model adaption. No idea why.

c) vehicle is not falling down after loosing wheel(s) - its an antigravity Area 51 bs

Any ideas ? I can actually send car .p3d, model.cfg and config.cpp files to someone via PM if he's interested in to help and take a look at it.

Thanks in advance!

[x3kj 1247]

a) would propably have to do with your the suspension/spring values, Those:

sprungMass = 350.0;

springStrength = 22600;

springDamperRate = 8680;

change them around to see what happens

b) make sure your memorypoints are named correctly

[Degman 73]

I tried deleting physx completely and still there remains that jumping problem. I checked all axis points, geometry LOD, conifg and model.cfg things, but I just see no problem - I really dont know where is car pumping that bug from. Same is for lights/dust. All memory points are 100% correct, they are properly defined in config, but however they doesnt work as they should be. That whole Octavia model is like cursed. I even tried using sample car parts from GEOLOD, physx LOD, selection names, adapting everything to A3 standards, but nothing changes. I am trying thousands of combinations for a whole week and there are always some problems with that zhing. Its like cursed, as I said. I think im just going to skip Octavia for now and wait for Vilas to start to work on Arma 3, so I can ask him for permission to use his Skoda Oct. model and files.

Octavia.rar - if anyone wants to take a look or use it for his own mod/addon

Edited June 27, 2014 by DegmanCRO