[ODE] Car Simulation(Lots of problems)

[Robson Ito]

hi. By bounce parameter i mean the restitution
parameter in the contact. yes, u r right, it have
something to do with the penetration. But it is not my
main problem..^^
"I'd assume that they fix
> themselves as 
> soon as you stop pushing?"
Yes. when i stop the controls everything go back to
normal. I really dont know but the wheels seen to lose
completely the axis align and the wheels seen to
rotate in an axis paralel to the chassis lenght for
example.
I'll try to explain the explode problem more detailed

if i have a car and an object:

velocity         wall   
-------->         |
 ______           |
|______|          |     
 0    0           |
------------------------------

velocity         wall, but i litte deformation  
-------->            |
 ______              |
|______|          |--     
 0    0           |
------------------------------

any idea?

sometimes the car is thrown so far (perhaps someting
to do with the horizontal part of the wall?) (rare)
sometimes the car sink in the ground (very rare)
and sometimes the system explode and the car
desappear(very very rare)

setting the contact ERP to less than 1 seen to
attenuate the ocurrence of this problems.

everything goes ok, but..when i have
                  
--- Jon Watte <hplus-ode at mindcontrol.org> escreveu: 
> 
> The ODE documentation actually addresses some of
> these issues.
> 
> I don't use Bounce in the demo. However, when you
> slam into 
> some object, the integrator has to apply enough
> force so that 
> you both negate the velocity into the object, AND
> you move 
> the object out of the penetration in the next time
> step. This 
> means that you will get some non-zero velocity out
> of the 
> penetration even with zero bounce. You can reduce
> this effect 
> by reducing the global ERP, but that will make the
> entire 
> simulation much squishier. You can also reduce the
> effect by 
> making the time step smaller, because penetrations
> during a 
> single time step will be smaller.
> There's no parameter named "bounce" so it's un-clear
> what you 
> are referring to -- Recoil? That's used when firing
> grenades. 
> 
> I haven't paid that much attention to the wheels
> when pushing 
> into static objects -- I'd assume that they fix
> themselves as 
> soon as you stop pushing? If so, it's probably just
> the 
> inherent flex of the joint (controlled by ERP)
> making itself 
> visible. It could also be the fact that the wheels
> are actually 
> spheres, but are drawn as cylinders (so you catch on
> the side 
> a little bit).
> 
> I haven't seen the system explode; I've tweaked the
> damping 
> applied so that it seems stable to me. However, you
> can probably 
> add more damping if you want to avoid some explosion
> I haven't 
> seen.
> 
> Cheers,
> 
> 			/ h+
> 
> 
> -----Original Message-----
> From: ode-bounces at q12.org
> [mailto:ode-bounces at q12.org]On Behalf Of
> Robson Ito
> Sent: Tuesday, August 10, 2004 12:54 PM
> To: ode at q12.org
> Subject: RE: [ODE] Car Simulation(Lots of problems)
> 
> 
> Hi..hey Jon Watte. it is a really good demo. i lost
> some time playing with it. The explosions physic
> effects is really good. 
> My problems with the car almost solved. Now it dont
> fall so easy. I got just 2 strange things happening.
> 
> When i am in front of a wall and keep acelerating
> against the wall the well seen to lose there Hinge2
> axis sometimes. (does it have something to do with
> the
> FudgeFactor??). I tried changing here and there, but
> got nothing. 
> the other problem, more complex, is that, them the
> car
> colide with a wall that is not a box, for example,
> if
> it is a user mesh, sometimes the car is throw far
> away, and sometimes the system seen to explode (very
> rare). 
> Another newbie question: does the Bounce parameter
> works? i tried to set it to 0 and nothing changed.
> the
> car still bounce in the walls.
> 
> Any help would be great..thanks.
> 
> 
> 	
> 	
> 		
>
_______________________________________________________
> Yahoo! Acesso Grátis - navegue de graça com conexão
> de qualidade! Acesse: http://br.acesso.yahoo.com/
> _______________________________________________
> ODE mailing list
> ODE at q12.org
> http://q12.org/mailman/listinfo/ode
> 
>  


	
	
		
_______________________________________________________
Yahoo! Acesso Grátis - navegue de graça com conexão de qualidade! Acesse: http://br.acesso.yahoo.com/