Different 'physics' on different tracks?

On a program like x-sim you can see the real in game values of the cars change as your driving. And developer is right. No hand of god here. The values of the car change the same proportional way whether on Silverstone or any other track. No magic glue, potion or anything.

@totalo. If you did some modding on track you'd realize how consistent the process is. One physic engine. Same track building engine but different shapes and sizes. Combine the car with the track and that's it.

Have zero fear. This is THE simulator.

 

I think that too, although I've never played GT so can't compare to it. Other than Silverstone and Imola (not so much), the tracks seem quite lifeless through ffb.
I've just updated my card driver and it's made a slight difference but will have to test more to be sure.

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Tracks have different grip, thats all.

 

The "swinging" sequence of turns at Vallelunga invites to drive faster than is recommendable. And not all cars can take the same turns at same gear. So I think it is about driving style.

 

In racing sims there are two driving physics models usually, one for low speeds and one for over that speed. In AC they have still not implemented the low speed physics model. That is why the cars have no body movement (body roll) when you stop, that is why the cars respond so strange if you slowly start driving from stopped. Once they add that model in then AC will feel more fluent and more realistic.

 

As for why that's necessary... Well, you can see ingame if you pop open the slip angle/slip ratio readouts that when you're stopped, they jump around randomly.

In both cases, you're comparing the vector of vehicle motion to the direction the tire's contact patch is going. So slip ratio = tirespeed/carspeed, eg. if wheel's turning at 110km/h and car's moving at 100km/h it's 1.1.

As speeds go to 0, this is numerically a problem. 0/0 is undefined - 1/0 is worse, it's +infinite. And it's not hard to have the tires going over 1km/h while the car's pretty near stopped in real life. Take burnouts for example... So you have to use a different method to determine the amount of force each tire is applying (and the direction). At a few km/h car speed, you can safely switch over.

So why are slip angle + slip ratio used if they have numeric problems near 0 speed? Well, cause they do a good job of explaining how tires develop grip IRL. No matter what (non-zero) speed you're going it seems to work correctly for determining the amount of grip. It's just got this low-speed hole.

 

Exactly, this can be quite a game-breaker for me.. I honestly hope it's some placebo effect, or that the track surfaces on those tracks will get more 'rough'.

 

Boris, Don't worry , read what staff member said. one physic engine.
If you play GTR2 simbin. Go on a tracks like spa, then go to lesser known tracks like Oschersleben, Enna Pergusa.

You will end up going back to spa because it feels better, like silverstone did for you. That's what makes a good track.
I'll do some more testing on Vallelunga tonight.