Exploding physics with stiff suspensions

Associat0r · Jul 7, 2016

So I just tried the RSR Dallara F3 which is supposed to have physics from real data.
But when I increase the rear wheel rates in combination with high fast rebound dampers in the garage, the physics engine sadly explodes.
https://i.gyazo.com/c9b4289203f11227aefdc7754ae950f3.mp4

EDIT: See here on how to reproduce it http://www.racedepartment.com/threads/exploding-physics-with-stiff-suspensions.123651/#post-2269476

Associat0r · Jul 8, 2016

mclarenf1papa said:
Oh forgot to mention, I was running a Group-C car with 7000lb/in front springs (an order of magnitude higher than anything in AC - as per the 1990 Nissan IRL...essentially a solid axle)...no issues whatsoever.

Give us the ride frequency and damping ratios.

mclarenf1papa · Jul 8, 2016

Associat0r said:
Give us the ride frequency and damping ratios.

lol that's fine by me
900kg, ~42% front, ~0.9 motion ratio....7,000 lb/in --> 11.5 Hz excluding tire stiffnesses. I was using generic damping ratios. If you want to do the frequency with tires and dampers included, knock yourself out...I'm not going to waste the time.

Associat0r · Jul 8, 2016

mclarenf1papa said:
lol that's fine by me
900kg, ~42% front, ~0.9 motion ratio....7,000 lb/in --> 11.5 Hz excluding tire stiffnesses. I was using generic damping ratios. If you want to do the frequency with tires and dampers included, knock yourself out...I'm not going to waste the time.

Well damping is majorly important in this case, as stated previously.

David Dominguez said:
It's mostly related to dampers (or used to be...)

And such cars are normally highly overdamped.

seanvdburg · Jul 8, 2016

I've never seen such a thing happen in my game, no matter what car I drive. You might be trying a setup that would not be possible in the real world. I think the mod allows values in the suspension setup that should not be possible to be selected.

Also increasing the simulation value might help cure the issue, it can do magic things!

Michael Hornbuckle · Jul 11, 2016

Has anybody else other than Associator been able to replicate this?

Jim Liak · Jul 11, 2016

Oh, why you keep adding more value in this troll thread?

Michael Hornbuckle · Jul 11, 2016

If it is a legit problem then it should be able to be easily reproduced which will then make it possible to be fixed.
I need the exact setup options that cause this behavior because I have been unable to reproduce the bug.

Jim Liak · Jul 11, 2016

If it is a legit problem, then the OP should report this to this mod's section and receive help from mod owner.
The game it's not supposed to support all values in all aspects.
As you said , KUNOS makes values to work for their sim and vanilla content.

If a make a Caterpillar 797F mod, I can't complain if the game won't support R63 tyres...

F_B · Jul 11, 2016

Jim Liak said:
If a make a Caterpillar 797F mod, I can't complain if the game won't support R63 tyres...

BUT WHY?!

Stereo · Jul 11, 2016

Michael Hornbuckle said:
Has anybody else other than Associator been able to replicate this?

Slide all 16 damper settings on the F312 fully to the max and it happens. It's a problem with the rear axle oscillating that seems to be most directly impacted by the rear fast bump/rebound. When I tune anything to below 95% of the max it stops (and the max is 14000, realistic in a race setup is like... 2000)

I kinda suspect it's also affected by rear bumpstops or something cause I've tried similarly stiff setups for other cars and it doesn't happen.

David Dominguez · Jul 11, 2016

I don't think this is a troll thread, I mean, it's not something new... and it already happened in rFactor (1) as well.

Brandon Wright · Jul 11, 2016

David Dominguez said:
I don't think this is a troll thread

Well, the OP is a known AC hater and it's quite likely the only reason he made this thread was to try to make AC look bad so he could carry on about how superior rF2 is. So, yeah, total troll thread.

Jim Liak · Jul 11, 2016

Brandon Wright said:
Well, the OP is a known AC hater and it's quite likely the only reason he made this thread was to try to make AC look bad so he could carry on about how superior rF2 is. So, yeah, total troll thread.

Which kind of backfired at him, since as David posted, this can also happen to the "superior" rf engine...

Associat0r · Jul 11, 2016

Jim Liak said:
Which kind of backfired at him, since as David posted, this can also happen to the "superior" rf engine...

I'm sorry to majorly rain on your minor parade, but rF1 is more than a decade old and that mod is most probably faulty anyway, yet the problem wasn't as severe as in the AC case.

Also, for reference, the excellent FR3.5 mod for AC is majorly less stiff than the one in rF2, because it would explode with real world values.

AC's physics instabilities still persist in general in the form exaggerated transmissibility, even when not exploding catastrophically, it also gets worse the farther you go from the world origin, that's also partly the reason why you won't see an Isle of Man in AC. And don't get me started on the aero breaking down on bankings, among many other issues.

It's also worth noting that rF2 uses totally new suspension code, as is almost all of its player physics code, which is majorly more robust than rF1 already was.

mclarenf1papa · Jul 11, 2016

Majorly.

F_B · Jul 11, 2016

What a boring life must someone have when he tells the same stuff over and over and over again? About a game. Please, Associat0r, do us all a favour and look for a new hobby. Or enjoy the nice weather and perhaps have a beer? Or even two?!

Radu Oros · Jul 11, 2016

Associat0r said:
Also, for reference, the excellent FR3.5 mod for AC is majorly less stiff than the one in rF2, because it would explode with real world values.

@David Dominguez is this true that the FR3.5 mod doesn't use real world values in AC? In case it was a problem back then, what would happen if you updated now the mod to «real world values»?

David Dominguez · Jul 11, 2016

It was an issue regarding ARBs, and what would happen is that the car would crash and fly like in that video, when using high settings.

Austin Ogonoski · Jul 11, 2016

David Dominguez said:
It was an issue regarding ARBs, and what would happen is that the car would crash and fly like in that video, when using high settings.

Well that was a broken WIP mod anyway.
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