Universal Wheel Physics

We're finally here!

Universal Wheel Physics, is raycast-based wheel behaviour solution alternative to standard Unity's wheel collider(WC). It is more stable, flexible and easier to use. You're not limited to use it as car's wheels. It can be almost everything: Plane's wheels, tank's wheels, or even you fancy robot that have wheels on its arms, head, use wheels anywhere you need! You're also not limited to use it rotated towards -Y axis like you are with standard WC. To make it as flexible as possible, it also doesn't solve steering internally, instead you just rotate your wheel's transform, so your vehicle's steering is natural consequence of changing direction of forces, not some fake-internal calculations.

Features:
-raycast-based
-well optimized, fully C# coded
-very similiar to Unity's inspector/API
-mobile friendly
-flexible: exposed as many options as could,while reamining simplicity of configuration
-automatic handling of visual wheel's rotation and positioning
-much more reliable and universal than standard Unity's WC
-mixing of forward/sideway forces
-finally you can have wheels on your vehicle's roof and sides!
-suspension forces affect other rigidbodies
-simulation of wheel's rotational inertia(you can adjust cars angle in air by accelerating/braking)
-uses realistic Pacejka's wheel friction curves(fully adjustable on the fly)
-friction curves updates automatically after every change to their variables
-smoothing of visual wheel movement(no more up and down wheel teleporting on square obstacles!)

Asset store: https://www.assetstore.unity3d.com/en/#!/content/41456
WebPlayer demo: CLICK
Have fun, post your opinion or feature request, all feedback is welcome!

 

I hope you will upload a webplayer to test it before buy it.

 

Customer wish is my command
WP will be up this weekend at the latest.

 

Waiting for this !!.

And if i want to make a drift car, can use this to make drift car ? is it optimized for mobile ?

 

Yes, drifting game should be no problem, also UWP's performance is mobile-friendly.
I should mention it in main description, thanks for reminder.

 

Yes, demo will be great

 

Web player demo is ready!
Updated first post.

 

So bought it, tried to make a motorcycle, bike falls to the side with 2 wheels. OK, fine tried 4 wheels, wheels are somewhat close together and only 2 visible wheels. Really hard to turn for some reason, and still falls to the side too easily. Could you maybe make a motorcycle example ?

 

Of course bike will fall on it's side, it's not complete vehicle physics solution, its 'only' wheel collider ( for 2-wheeler you would need fake gyroscope-like forces, but it should't be hard, for start I would recommend applying torque force in your bike's Z axis opposite to leaning ).
Regarding 4-wheeler - did you setup everything as in example scene? If you don't succeed with example scene, try doing step by step instruction in manual, I explained there how to setup wheels so they will position and rotate properly.
If you will still have problem with visual wheels, send me your project(vehicle on empty scene), and I'll check what's the problem.
But it really isn't anything fancy you just have to set your's visual wheel transform, so that it's axis is aligned with X axis, and pivot is in it's center. Let me know if you succeed with it

 

One question, in your wheel physics, do you add Torque for Acceleration and Brake like Wheel Collider or, it can be made in another way?

 

Hi Roni,
This looks really good! Is the demo car rig included?

 

I don't know if I understood your question, but yes, it uses addTorque on acc/braking for simulating rotational inertia.

Yes, of course

 

Hello,

How can I check if the wheel is grounded? Like stock WheelCollider.isGrounded

Thanks

 

Pretty sure this tools has an equivalent.

 

Oh ye? Well what is it then? I bought it and I cannot find the equivalent

 

Yes, it's my little oversight - there is "contact" variable, but it's private. Fix is on way. In the meantime you can fix it by yourself just by changing contact variable to public in UniversalWheel.cs class. It should work exactly like Unity's isGrounded.

 

@Roni92pl , is possible to have a "big" torque without having "big" speed?, like a Truck for example, that have big torque to move the high loads and with very low speed.

 

Sure. Just limit torque when your target rotational velocity is reached.

 

Hi @Roni92pl

I can not play webplayer via your website (not problem of using Chrome). Could you upload the latest version of webplayer build into dropbox or something other host, so i can download it ?

Thanks

 

Hello, we got some small update! The most important change is that fluent wheel movement system is no beta feature anymore, as it works perfectly now. Changelog:
v1.1:
UniversalWheel class:
-new property: SidewaySlip and ForwardSlip (read only)
-new property: HasContact (read only)
-new function: GetGroundHit
-feature: fluent wheel movement system 'lag' fixed
-general little cleanup of code and comments

 

Hmmm... I don't get it. Can you describe in few words - why this asset better than wheel collider?

 

I would recommend you to familiarize yourself with this thread: http://forum.unity3d.com/threads/unity-5-wheelcollider-component-is-unusable.307099/
And then to look at our features. The biggest advantage imo is that you are not limited to use it on Y-axis.

 

Ok, do you have plans to make some limited version or trial? So I can try it before buy

 

Sorry, no other version is planned. But there you have WebPlayer demo where you can try its behaviour.

 

Hey Roni92pl. Great work on the wheel physics.
I´m interested in buying, but i heard that these physics are very unstable for bikes/2 wheeled vehicles. I would like to know if they can be adjusted to work with 2 wheels. Maybe removing the Suspension code all together would help, because for my bike physics game, it is not needed at all. If you help me figure this out, im gonna buy your asset. Thanks and waiting for your reply.

 

Hey Vossyy, it so happens that few days ago I helped one folk with just the same issue(or very similiar?). It was 2d bike platformer, and we managed to have almost "non suspension" behaviour on his bike, just by setting very stiff suspension. So, yeah basically its feasible, just keep in mind it won't be 100% non movable wheels, they will always move a little on jumps and bumps. But again, you can lock your visual wheels to not move and you can have pretty convincing effect, and a little movement of physical wheel can be interpreted as tyre compression then

 

Hi, do you think is possible to extend your script to support multiple raycasting (at different angles) and collision points on each wheel?
The main reason is to avoid a wheel to enter inside an irregular terrain or inside a wall and, at the same time, apply the correct forces based on the hitting points and hit normals.
Also would be even better if the suspension could have a two dimensional range limit instead of just a line.
Thanks.

 

I dont think many raycasts would be a good solution for that case. I was working on wheel with real physicall shape( cylidner) with slip-based friction instead of raycasts. The problem was that you can't calculate contact force, because there is no any compression, like in raycast. I mean, you can calculate force of hitting wheel to the ground, but what when it is already touching it? There was no way of getting this force when I was working on it.
They added recently this - http://docs.unity3d.com/ScriptReference/Collision-impulse.html
So I guess it's maybe feasible now.

 

Hi there, is there any chance you can add a smooth follow camera to the webplayer demo? I really can't evaluate it properly with the current camera setup that is fully locked to the car.

 

Thank you. I sent you a private message.

 

I would also like to see a couple more camera options, a look at and a free camera so can better judge the physics. Is it also possible to make it easier to do drifting and doughnuts?

 

If I have some complex tank suspension like this - http://forum.valka.cz/files/t26m-002-uprav_167.jpg
will this asset work good enough? At the moment I am not so happy with standard Unity Wheel Collider

 

Hmmm... it seems like this thread is not so active... I just don't want to lose 20$
Is this asset good for complex tank suspension?

 

Hi, I dont know how you want to solve this suspension, so it's hard to answer. It's generally raycast with addForce affecting rigidbody you select. So it's more of question what YOU can do with it

 

Any chance of an updated webplayer with different cameras?

 

Is the demo down? EDIT: Apparently the demo works in Firefox on Windows, but for some reason, the link redirects me to http://www.ronisvision.com in Safari on OS X.

One thing I am looking for is the ability to lock wheels together as if they are on a single axle. Does your solution support this?

 

Hmm, good question. The answer is yes, and no. Yes, because you can attach it to axle that has its own rigidbody and it will work, but no, because you can't "remove" suspension calculations-wheels will just have suspension working relative to your axle instead of main vehicle's rigidbody. But I do custom physics solutions, pm me if you are interested.

 

I think there may be some confusion about what I am looking for. When I say lock the wheels together as if they were on a single axle, I am referring to the rotational velocity of the wheel, not the suspension. So the wheels are always spinning the same speed when the "differential" is locked, and when it is unlocked, they can rotate independently.

I actually want the suspension to work independently, so that is good.

 

Hmm, I see what you mean now. There is no any engine/drivetrain logic implemented, it's replacement for Unity's wheel collider, and have very similiar functionality, that you can use to create drivetrain, engine systems etc(by using torque/brake forces on wheel).

 

Hi.
I bought your Assist, and the question of how to make a car with four-wheel drive?

 

Use axisTorque to apply torque on four wheels. Check manual to see api.

 

Hello,

I also have a question.
First of all i am happy with your asset!
But i am having a little trouble with it, i have a "Car" with 4 wheels attached and it is all working as it should.
But once the car is flipped upsidedown the wheels go into the ground.
I thought i ask here before i alter any of the code too much, i saw that the raycast is Always casting "transform.up".
Is there a way to make it raycast all sides without loosing too much performance?

The wheels also jump into the air once you drive onto an obstacle lets say a small cube. is there a fix for this aswell?

Regards

 

Hi, sent you pm.

 

I would also like to see a couple more camera options, a look at and a free camera so can better judge the physics. Is it also possible to make it easier to do drifting and doughnuts?

 

You would need to apply some external force, I guess, or manipulate wheels friction when need to drift.

 

Can we use this wheel with other car physics engine ?. Say Realistic Car Controller or Edy's Car Physics.

 

I don't see the point, but yeah, integration shouldn't be hard, and definitely feasible.

 

Hi Roni,

thanks for you asset. I recently bought it and it works great! Now I want my car to move on a moving platform. But it seems that your WheelCollider doesn't take the ground velocity into account and the plattform slips away under the car. Any ideas how to implement it? Thanks in advance!

 

Yes, I had such feature in plans, but sadly due to lack of time I had to abandon it.

 

What do you mean in this step, I know, I'm kinda dumb, I dont even understand the instructions (such a noob) but may you answer me?
-Drag your vehicle's root to rigidbody field of UW, to assign our vehicle's rigidbody