As most know already, rally cars tend to slide around corners and the such much more than any other vehicles. Using external forces to turn your vehicle works perfect for rally car simulations. Though, it works horrible for anyone who wants their vehicles to turn precisly. Since you have to decrease the friction, the vehicle also slides very far while performing a turn. Again, good for rally car racers, very bad for anything else according to my current observations.
Could you add a feature that allows precise turning regardless of the friction value? I would really like to be able to change a models orientation using pan while in the physics engine, since phent_addtorque and phent_addforce do not turn the vehicle very precisly. Thanks, I hope to hear what type of a solution you can come up with for this, since I'm almost all out of ideas.

Here's my current script, you will be able to understand what I mean about turning and the such by implementing this. Remember, call "Flex" from the main function. Also, be sure to have 2 completely horizontal vertex positions on your vehicle. You will notice that I use these 2 vertices to find the angle of the vehicle, that way I know what direction to apply the force in. As always, please share any insight on the script, since I am not a complete expert with external forces, and perhaps - there is a great way to have precise turning after all. Hope this helps. Thanks.

Code:

---

  





//---------------------------------------------------------------------------------------------------------------------------

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::Variables(Defines)::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//---------------------------------------------------------------------------------------------------------------------------



//Wheel & Kart Defines

entity* player;

entity* wheel_fr;

entity* wheel_fl;

entity* wheel_bl;

entity* wheel_br;



var FR_wheel_ID;

var FL_wheel_ID;

var RL_wheel_ID;

var RR_wheel_ID;



var p1[3];

var p2[3];

var p3[3];

var p4[3];

var p5[3];

var p6[3];



//Environment Defines



var earth_gravity[3] = 0,0, -316;

var mars_gravity[3] = 0,0, -316;



var wheel_friction = 90;

var wheel_mass = 90;

var wheel_bounciness = 0;

var wheel_minimumSpeed = 0; 



var kart_mass = 30; 

var kart_friction = 40;

var kart_bounciness = 0; 

var kart_minimumSpeed = 0; 



// Movement Defines

var m1_1[3];

var m1_2[3];

var m2[3];

var wheel_target;



//---------------------------------------------------------------------------------------------------------------------------

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::PowerSlide(settings)::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//---------------------------------------------------------------------------------------------------------------------------





//---------------------------------------------------------------------------------------------------------------------------

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::Kart(settings)::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//---------------------------------------------------------------------------------------------------------------------------



var air[3];

var force[3];



action kart // the kart action

{

my.pan += 180;

p_player = me;



p_player.overlay = off;

p_player.flare = off;

p_player.bright = off;

p_player.transparent = off;

p_player.ambient = 50;



ph_setgravity(earth_gravity);

phent_settype(my,PH_RIGID,PH_box);

phent_setgroup(my,2);

phent_setmass(my,kart_mass,PH_poly);

phent_setfriction(my,kart_friction);

phent_setelasticity(my,kart_bounciness,kart_minimumspeed);



wait(10);



while(1)

 {



   if(key_f == 1) //Jump Up

   {

    wheel_target = 0;



    phent_addcentralforce( p_FR_tyre, vector(0,0,90000000));  // this is the jump strength

    phent_addcentralforce( p_FL_tyre, vector(0,0,90000000));

    phent_addcentralforce( p_RL_tyre, vector(0,0,90000000));

    phent_addcentralforce( p_RR_tyre, vector(0,0,90000000));



    phent_addcentralforce( p_player, vector(0,0,900000));

   }

 wait(1);

}

}  



//---------------------------------------------------------------------------------------------------------------------------

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::Control::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//---------------------------------------------------------------------------------------------------------------------------





Function Flex() // Call this from main

{

 var s_vert1[3];

 var s_vert2[3];

 var s_angle[3];

 var s_force[3];

 var z_force[3];

 var f_orce[3] = 8880,0,0;

 var f_orcer[3] = -8880,0,0;



phent_setdamping (p_FR_tyre, 0, 100 );

phent_setdamping (p_FL_tyre, 0, 100 );

phent_setdamping (p_RL_tyre, 0, 100 );

phent_setdamping (p_RR_tyre, 0, 100 );



phent_setdamping (p_player, 0, 100 );



 while(1)

  {

   vec_for_vertex(s_vert1.x,p_player,49);  // base vertex

   vec_for_vertex(s_vert2.x,p_player,51);  // tip vertex



   // Get the angle from the base to the tip of the kart, and store it in angle[3]

   vec_set(temp,s_vert2.x); 

   vec_sub(temp,s_vert1.x);

   vec_to_angle(s_angle,temp);



   vec_inverse(temp);

   vec_scale(temp, 0.5);

   vec_set(s_force.x,nullvector);

   s_force.x = 90000; // how fast the skid is

   vec_rotate(s_force.x,s_angle);



   vec_set(z_force.x,nullvector);

   z_force.x = -90000;

   vec_rotate(z_force.x,s_angle);



if(key_d == 1) // Turn

{

   phent_addtorqueglobal(p_player, vector(0,0,-8000)); 

 //phent_addforceglobal (p_player, f_orce, vector(2000, 2000, 0));

}



if(key_a == 1) // Turn

{

 //phent_addforceglobal (p_player, f_orcer, vector(2000, 2000, 0));

   phent_addtorqueglobal(p_player, vector(0,0,8000));

}



   if(key_w == 1) //Accelerate

   {

    wheel_target = 0;



    phent_addcentralforce( p_FR_tyre, s_force.x); //Accelerate

    phent_addcentralforce( p_FL_tyre, s_force.x);

    phent_addcentralforce( p_RL_tyre, s_force.x);

    phent_addcentralforce( p_RR_tyre, s_force.x);



    phent_addcentralforce( p_player, s_force.x); 

   }



   if(key_s == 1) //Reverse

   {

    wheel_target = 0;

    phent_addcentralforce( p_FR_tyre, z_force.x); // Reverse

    phent_addcentralforce( p_FL_tyre, z_force.x);

    phent_addcentralforce( p_RL_tyre, z_force.x);

    phent_addcentralforce( p_RR_tyre, z_force.x);



    phent_addcentralforce( p_player, z_force.x); 

   }



 wait(1);

 }

}



//---------------------------------------------------------------------------------------------------------------------------

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::FrontLeft(Wheel)::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//---------------------------------------------------------------------------------------------------------------------------



action fl_wheel

{

my.pan += 180;



	p_FL_tyre=my;



	phent_settype(my,PH_RIGID,PH_sphere);

	phent_setgroup(my,2);

	phent_setmass(my,wheel_mass,PH_sphere);



	phent_setfriction(my,wheel_friction);

	phent_setelasticity(my,wheel_bounciness ,wheel_minimumSpeed);

	phent_setdamping(my,20,20);

	

	vec_set(p2,vector(0,0,1));

	vec_set(p3,vector(0,1,0));

	vec_set(p4,vector(-40,40,0));

	vec_set(p6,vector(0,0,0));

	FL_wheel_ID=phcon_add(PH_WHEEL,p_player,my);

	phcon_setparams1(FL_wheel_ID,my.x,p2,p3);

	phcon_setparams2(FL_wheel_ID,p4,nullvector,p6);

}



//---------------------------------------------------------------------------------------------------------------------------

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::FrontRight(Wheel)::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//---------------------------------------------------------------------------------------------------------------------------



action fr_wheel//front right tire

{

my.pan += 180;



	p_FR_tyre=my;

  

	phent_settype(my,PH_RIGID,PH_sphere);

	phent_setgroup(my,2);

	phent_setmass(my,wheel_mass,PH_sphere);



	phent_setfriction(my,wheel_friction);

	phent_setelasticity(my,wheel_bounciness ,wheel_minimumSpeed);

	phent_setdamping(my,20,20);

	

	vec_set(p2,vector(0,0,1));

	vec_set(p3,vector(0,1,0));

	vec_set(p4,vector(-40,40,0));

	vec_set(p6,vector(0,0,0));

	FR_wheel_ID=phcon_add(PH_WHEEL,p_player,my);

	phcon_setparams1(FR_wheel_ID,my.x,p2,p3);

	phcon_setparams2(FR_wheel_ID,p4,nullvector,p6);

}



//---------------------------------------------------------------------------------------------------------------------------

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::BackLeft(Wheel)::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//---------------------------------------------------------------------------------------------------------------------------



action bl_wheel //back left tire

{

my.pan += 180;



	p_RL_tyre=my;



	phent_settype(my,PH_RIGID,PH_sphere);

	phent_setgroup(my,2);

	phent_setmass(my,wheel_mass,PH_sphere);



	phent_setfriction(my,wheel_friction);

	phent_setelasticity(my,wheel_bounciness ,wheel_minimumSpeed);

	phent_setdamping(my,20,20);

	

	vec_set(p2,vector(0,0,1));

	vec_set(p3,vector(0,1,0));

	vec_set(p4,vector(0,0,0));

	vec_set(p6,vector(0,0,0));

	RL_wheel_ID=phcon_add(PH_WHEEL,p_player,my);

	phcon_setparams1(RL_wheel_ID,my.x,p2,p3);

	phcon_setparams2(RL_wheel_ID,p4,nullvector,p6);

}



//---------------------------------------------------------------------------------------------------------------------------

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::BackRight(Wheel)::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//---------------------------------------------------------------------------------------------------------------------------



action br_wheel

{

my.pan += 180;



	p_RR_tyre=my;



	phent_settype(my,PH_RIGID,PH_sphere);

	phent_setgroup(my,2);

	phent_setmass(my,wheel_mass,PH_sphere);



	phent_setfriction(my,wheel_friction);

	phent_setelasticity(my,wheel_bounciness ,wheel_minimumSpeed);

	phent_setdamping(my,20,20);



	vec_set(p2,vector(0,0,1));

	vec_set(p3,vector(0,1,0));

	vec_set(p4,vector(0,0,0));

	vec_set(p6,vector(0,0,0));

	RR_wheel_ID=phcon_add(PH_WHEEL,p_player,my);

	phcon_setparams1(RR_wheel_ID,my.x,p2,p3);

	phcon_setparams2(RR_wheel_ID,p4,nullvector,p6);

}



//---------------------------------------------------------------------------------------------------------------------------

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::Control(Input)::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//---------------------------------------------------------------------------------------------------------------------------



function control()

{

	while(1)

	{

		if(key_a == 1)

		{

			wheel_target=-40;

		}



		if(key_d == 1)

		{

			wheel_target= 40;

		}



		if(key_a == 1 && key_d == 1)||(key_a == 0 && key_d == 0)

		{ 

			wheel_target=0;

		}

	  



vec_set(temp, p_player.x); // makes it so temp is always starts at my.x

temp.z -= 4000; // set how far to trace

air = c_trace(p_player.x, temp,ignore_me+ignore_sprites+ignore_models); // see's if player will hit ground sometime



if(air > 30) //if the player is still in the air

{

 ph_setgravity(mars_gravity);

 wheel_target=0;

}

else

{

 ph_setgravity(earth_gravity);

}

		phcon_getposition(FR_wheel_ID,temp);

		vec_set(m1_1,vector((wheel_target-temp.x)*0.2,500,0));

	

		phcon_getposition(FL_wheel_ID,temp);

		vec_set(m1_2,vector((wheel_target-temp.x)*0.2,500,0));

		

		phcon_setmotor(FR_wheel_ID,m1_1,m2,nullvector);

		phcon_setmotor(FL_wheel_ID,m1_2,m2,nullvector);

		wait(1);

	}

}



//---------------------------------------------------------------------------------------------------------------------------

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::Create(Player)::::::::::::::::::::::::::::::::::::::::::::::::::::::

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

//---------------------------------------------------------------------------------------------------------------------------



action Need_Me //faulty action

{

	phent_settype(my,PH_RIGID,PH_sphere);

	phent_setgroup(my,2);

	phent_setmass(my,wheel_mass,PH_box);

}



function create_player()  

{  

 ph_setgravity(vector(0,0,-380));	

 ph_setcorrections(30000,0.05); 



 ent_create(mdl_car, temp, kart); 



 vec_for_vertex(temp,p_player,627);

 wheel_fr =	ent_create(mdl_tyrefr,temp,fr_wheel);



 vec_for_vertex(temp,p_player,618);

 wheel_fl =	ent_create(mdl_tyrefl,temp,fl_wheel);



 vec_for_vertex(temp,p_player,614);

 wheel_bl =	ent_create(mdl_tyrebl,temp,br_wheel);



 vec_for_vertex(temp,p_player,634);

 wheel_br =	ent_create(mdl_tyrebr,temp,bl_wheel);



 vec_for_vertex(temp,p_player,634);

 wheel_br =	ent_create(mdl_tyrebr,temp,Need_Me);

}

---

I tried the script, but you have made some last minute variable changes (I guess) which is why it won't compile. After doing several search and replaces I got it to compile but it's not moving at all.

Did you get it to work for you yet Marco? If it still does not work, please tell me what the errors are. I'd like to know, since once you do get it to work for yourself, I have a few questions about adding forces to the wheels so you can turn better. Thanks.


BTW - It works for me fine.

Can you send me a ZIP with all required files? I can't integrate into my current car script.

Okay, i'll throw together a quick car model that works with the code and send it to you. Since I cannot send you my kart model. Expect it in 2 days or less.

sorry, didnt see the date of the post... Please post all findings of this script since we're dying to have a good car-on-terrain script!


BTW, is this script implementing the 'fix' that was done a week or 2 ago?

thanks
Jason

Sorry Marco, but i've been very busy lately. I'll send the car code with car model and tires next week. Again, sorry about that.

Making major changes to it, such as getting rid of all that external vertex checking junk...

I almost have it!!!! After about 12 hrs of work on adding to my old vehicle code(see above), I just about have it perfectly working with 0 friction! Yes that's right, 0 friction! It actually moves like there is perfect friction applied to it, and turns like the wheels are turning it. Best of all - there is no flipping, no wheel bending, and you can go up ramps with ease. Thanks Conitec for making this possible with phent_getvelocity,a variety of vector commands and most importantly the commands to add forces and torque. I'll most likely post it in a few days, just got alot of tweaking now... figured i'd keep everyone updated on my situation.

Awesome! Some of us are awaiting the results of your efforts! Too cool i say


Jason

Sounds very interesting, but sorry for not paying attention while reading, is this using only 1 body or 4?(chassis+4 wheels)

~Phantom88~