MRengine sliding problem (also present in stock) VIDEO proof Included.

Darthtool
Posts: 5
Joined: Wed May 02, 2018 2:06 pm

MRengine sliding problem (also present in stock) VIDEO proof Included.

Post by Darthtool » Wed May 02, 2018 3:14 pm

Video of problem... watch carefully. https://www.youtube.com/watch?v=ukqwV129kfo&t=1s


This is related to Stock game environment and modded (More realistic engine) and im pasting my post from the Fs-uk forum here.

To Summarize, Inactive vehicles (engine off) lose all their physics/Mass and traction.. in the base game without MRengine this isn't to much of an issue on hills, but with MRengine and added mass everything slides away like on ICE, the Debug mode shows active vehicles have an effect on Non-active vehicles in close proximity and this is the root cause of the problem.



If i place two vehicles side by side on a steep slope (with or without handbrake mod) and start the engine on one of the vehicles and move it slightly the other vehicle loses all traction and slides away. if the engine of both tractors is on neither will slide away.

so basically an inactive tractor with engine off on a hill will stay put until i drive close to it with another tractor in which case it then acts like the ground is ice and falls away.

I am using crop destruction modules and MR, is this a game bug or something MR causes?

(AFTER SOME TESTING)

It appears that any MR modded vehicle exhibits (except tracked units) this behavior where-as standard un-moddfied vehicles d'ont, could this be a problem with the MRsetmass feature?

another area this shows itself is when trying to hook upto a loaded trailer on a hill, the second you touch it or get near it with MR activated it rolls away like its on an ice sheet, wheels not spinning.. its as if the game forgets the physics.


With the game stock there still appears to be an effect on inactive vehicles when an active vehicle is driven close to it, it shows a slight jump on the inactive vehicle.. its this effect with MR enabled that then results in complete loss of traction of that inactive vehicle. (you can push a 16ton tractor sideways with a 3 ton tractor for example until you switch the engine on in the inactive vehicle)

Is this related? loss of tire mass? https://www.fs-uk.com/forum/index.php?topic=200014.0

Using DEV-mode and looking at the collisions boxes i notice there seems to be an area of effect on the active vehicle which appears to effect the traction of any vehicle in proximity. (the white ring on the wheels lights up and physics become active/inactive)

TLDR... MR exacerbates a stock game bug/issue, is their a work around or is this a "Feature" we have to put up with Smiley

Stegei
GIANTS Software | CTO
Posts: 1453
Joined: Sat Jun 09, 2007 10:51 am

Re: MRengine sliding problem (also present in stock) VIDEO proof Included.

Post by Stegei » Wed May 02, 2018 4:08 pm

This can be due to many different issues. Without knowing any details, I would recommend looking at the following points:
-Wrong forcePointRatio values for the wheels (try starting with 1.0, if it helps, decrease the value until the tipping behavior is ok and it's still not sliding. If it is too small, the tire forces are applied above the center of mass of the vehicle, which leads to really bad effects)
-Move the Center Of Mass up (alternative to increasing forcePointRatio)
-The mass of the front axle could be too small (large differences between masses make the whole simulation unstable)
-The friction or lat/long stiffness could be too small
-The masses of the wheels could be wrong (making them too small can lead to an unstable simulation)

Darthtool
Posts: 5
Joined: Wed May 02, 2018 2:06 pm

Re: MRengine sliding problem (also present in stock) VIDEO proof Included.

Post by Darthtool » Wed May 02, 2018 4:52 pm

The problem only occurs when the active player vehicle is in close proximity to the inactive vehicle, if you turn the engine of the in-active vehicle on as well then the problem goes away.

As in the video you can see that when the active player controlled vehicle moves it seems to also affect/remove the physics from the inactive vehicle. i've tested this with nearly every MR modified tractor on the database and the converted ingame tractors/trailers.. same problem with the same intensity.

i placed two tractors side by side on a steep incline with their engines off, i stopped next to these tractors with another and inched forward and backwards.. everytime the game registered my throttle response one of the inactive tractors began to slide backwards and stop when my inputs were stopped, this seems to be more of a game issue than the mod..

I think the Mod just highlights an issue that wasn't present with the less realistic arcade settings.

visually in the DEV collisions mode it appears like the simulation stops after a few seconds of no player input, would it matter what settings were in the XML file if the game was no longer simulating the vehicle?

the effect of the active tractor affecting the inactive tractor when moving is present in the un-modified game as can be seen in the Debug mode, but the sliding action is much less or almost non existant.

Obviously im not a programmer so this is hard to explain but i think all the evidence is there in the video if you know what you are looking at, collision boxes/activations etc.

Stegei
GIANTS Software | CTO
Posts: 1453
Joined: Sat Jun 09, 2007 10:51 am

Re: MRengine sliding problem (also present in stock) VIDEO proof Included.

Post by Stegei » Thu May 03, 2018 7:34 am

The issue is not that the simulation stops or starts. That is to be expected. For performance reasons, we stop the simulation for any object as soon as it is not moving anymore (or only moving slowly). If another object comes close by or we add any force to it (like pushing the throttle) it will be activated again.

The issue you are seeing, is that the simulation of that tractor in the video is not stable for some reason, thus it is sliding even though it should not. The only reason that it does not slide all the way down the hill without your interaction is the above described deactivation of the simulation because it is only moving slowly and thus get deactivated.

Did you try the same scenario with no mods at all and a simpler stock vehicle that has no front axle? (like the Lizard Pickup Rodeo?) How about one of the stock tractors with a front axle?

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