[ODE] Car Simulation(Lots of problems)

[Jon Watte]

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.


	
	
		
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