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I'e learned something special about RollGrip in Physics.con

Posted: Mon May 07, 2012 11:05 am
by dudejo
Basically, it's the only setting of ObjectTemplate.Grip which interacts properly with the ground's resistance and (maybe) friction values.

At first, I always thought that setting more of a vehicle's wheels to EngineGrip was responsible for the massive acceleration boost but while I was playing around with the Greyhound physics, I simply set two wheels to EngineGrip and the rest as EngineDummyGrip.

Behold, I was getting the same "peppy" boost of acceleration even though I had less drive wheels than before!

So yeah, I wanted to share my observations since it's not something that seems immediately obvious.

Re: I'e learned something special about RollGrip in Physics.

Posted: Tue May 08, 2012 3:55 pm
by Swaffy

Re: I'e learned something special about RollGrip in Physics.

Posted: Wed May 09, 2012 12:32 am
by dudejo
It doesn't really mention what I just said.

with the ground material's values remaining the same, Having wheels with or without RollGrip makes all the difference.

Basically, a properly modelled wheeled vehicle NEEDS RollGrip on at least a couple of wheels. The only exceptions I can think of are vehicles with locking differentials on every axle or tracks.

Re: I'e learned something special about RollGrip in Physics.

Posted: Wed May 09, 2012 5:56 pm
by fo0k
Ahh yeah nice find dude.. I also assumed it was the engine grip that caused this.

so can now get better traction without the need for 4WD basically?

Re: I'e learned something special about RollGrip in Physics.

Posted: Wed May 09, 2012 10:54 pm
by dudejo
For the Willy at least, you can set the Engine wheels in front with the RollGrip wheels in the back.

It's not ideal, since the Willy would logically have one in front and one in the back (caused by its non-locking differentials). However, you can't turn properly and the vehicle pulls to one side as you accelerate, even if the Engine wheels are on opposite sides.

EDIT : After testing, the Willy behaves fines with a front left and back right Engine wheel (or its faults are very subtle). However, I remember the Black Medal having problems with pulling to one side when using such wheel configs. Although I'm not entirely certain if the differential would favor one side or the other since whatever pictures I found of the drivetrain have the differential being smack in the middle of the axle. Torque steer seems unlikely so a Front-wheel setup would probably work better. Especially since the Black Medal's 4WD system is supposedly unreliable according to what personal research dug up.