What kind of force to use on vehicle

Unity Engine
1

So what I am scripting it a tractor vehicle now there are major differences with a tractor then a car and I trying to get is as realistic as possible. So with a factor u have to set a gear and then release the clutch and the tractor goes then u can slightly increase speed by upping the throttle. So I can script everything just fine the only trouble I having is with the forward motion. What I want to happen is that when player pushes W it releases the clutch and the tractor starts moving at a constant speed. So I script for when the w key pressed that a constant force is added to the tractor. That works like I want then I added the turning part of the script, it turns just fine but yet I’ll keep turning to where the tractor is turned all the way around and with the constant force applying to it, it still goes same direction so the vehicle looks like it moving backward when I want it to be moving wherever the tractor is facing.

Is there something different I should be doing or should I use relative force and apply in fixed update but to me it seems to be speeding up. Any insight from anyone would be greatly appreciated. Thanks

Tainted

2

As a concept, your basically wanting to create a vehicle. This vehicle needs wheels and some other things about physics to make it happen. There are a number of tutorials out that deal with this in different ways. I created a simple basic tutorial, then expanded on it to a full running game.

http://forum.unity3d.com/threads/86703-Basic-to-Advanced-Car-or-Vehicle-Tutorial

I would suggest starting in the physics world where you have a wheel that turns creating your motion, instead of adding force.

My tutorial does not cover constant force, however, you could easily add that into it.

3

I have looked at your tutorial, and it is very good, i have taken parts of code from it. My only problem I am having is using motorTorque on the back wheels, when this happens starts out good, but then all of a sudden the tractor seems like is is doing donuts/fish tails and not going straight it viers off to most of the time the left, when i have no input of steering controll, any suggestion to a fix?