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elchtest mod :)
02-04-2010, 12:04 PM,
elchtest mod :)
Recently, I rewrote the way the wheel forces are calculated. I think it's good enough to be committed.
Ladies and gentlemen, the Elchtest modification. :lol:
[Image: 1997_elchtxsbs.jpg]
So please check out and test.
PS: I think we need a car reset button. Smile
02-04-2010, 01:01 PM,
Oops, ABS is broken. Bugfix is wip.
02-04-2010, 02:16 PM,
ABS is back in rev2588.
02-04-2010, 02:41 PM,
Great job!
02-05-2010, 11:29 AM,
Can you describe what you changed? I'm still making my way through the changelogs but don't quite grasp it yet. :-) I did notice that the C7 likes to roll on a lot of corners now.
02-05-2010, 11:39 AM,
1.) Applying tire force at contact point(it was applied at wheel center before).

2.) Change the way tire/brake lock up is calculated. The idea is that the maximum applicable brake/rolling_resistance torque is the wheel lock up torque(torque that reduces wheel angular_momentum to zero).

3.) I'd like to have rolling_resistance depend on tire normal force. It doesn't work now, as the wheel/suspension is following the surface displacements(velocity = (displacement - last_displacement)/dt) and we are getting huge normal forces on bumpy surfaces.

The initial commit was a bit too early. So multiple bugfixes followed. I think it should be correct now. Sorry for change log pollution. :oops:
02-05-2010, 01:10 PM,
OMG! I haven't tested the mod with the new cars. A lot of them have way too much traction(rolling over all the time). Need to look into car parameters after supension modificiation.
02-05-2010, 04:15 PM,
Found/fixed a bug in tire normal force calculation(suspension force magnitude was used before, even if the force was negative relative to wheel up-vector). Now the cars should behave more civilized.
02-06-2010, 12:25 AM,
Well the change seems to feel pretty good with most of the cars, it may just be that the C7 needs some parameter adjustment (it still seems to flip pretty easily, but it did that some before too).
02-10-2010, 08:37 AM,
No need to change C7 parameters. I rewrote the wheel camber calculation. The previous was returning wrong camber angles. Rollovers should be gone now.
02-10-2010, 11:25 AM,
I have noticed some regressions with the latest changes.

1. Car will move indeterminately after a forced rollover. This is related to the way suspension is simulated. Suspension returns huge overtravel values on rollover. Overtravel is added to car position.

2. The AI cars have problems starting a race. Maybe a bug in Autoshift/Autoclutch. Can somebody confirm this one?
02-10-2010, 06:58 PM,
NaN Wrote:2. The AI cars have problems starting a race. Maybe a bug in Autoshift/Autoclutch. Can somebody confirm this one?

yeah i can confirm, the ai is stuck on full throttle. ramming into them makes them roll away so no breaks are applied. and when hitting them the rpm's drop shortly and return to normal.

another thing is that drifting points aren't calculated anymore
02-10-2010, 07:36 PM,
OK, my second attempt on tire force calculation. I have been calculating the tire forces in wheel space(relative to wheel). This is wrong. They have to be calculated relative to road surface(tire space).

Thanks for the reply! It looks like the car wheels are not on track. So no drift score and no lap times. Will fix asap.
02-10-2010, 08:19 PM,
another thing that i noticed is that whenever the wheel(specifically the tire) lifts off of the track and collides with a wall or cone i either get the game crashing and a

INFO: Car loading was successful: TC
vdrift: src/cardynamics.cpp:167: void CARDYNAMICS::ComputeSuspensionDisplacement(int, double): Assertion `!isnan ( wheelheight_above_ground )' failed.
SIGABRT detected, releasing the mouse

or the car appears way below the track spinning every which way and the wheels separate from the car

[Image: 1_bug.jpg]

edit: it actually seems like the track disappears. it's easy to replicate in the NS, i just weave back and forth and hit the break and all of a sudden the car is falling and shaking violently. if i move the camera around i can't find the track anywhere.
02-20-2010, 05:47 PM,
Car rollover/wheel collision misbehavior should be fixed now(rev2613). Testers are welcome, as usual.

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