Wheeled Vehicle: Collision not working?

Hey there!

Been working on a 3 wheeled vehicle. My setup is: xform -> link the wheels to the mesh -> z up export. Right now, im sitting on this problem for almost 2 weeks and cant find a solution to it. Tried almost everything now.

Im using UE 4.12.5

The physic assets looks fine, although the backwheels seems to spine off in the wrong direction, its seems to be standing correctly now (it felt always to the side before). As you can see, the axis are also correct. Changing the mode to kinematic wont make a difference.

Here are my vehicle setup:



Radius is measured and correct. The front wheel has the same settings, except the radius. The reason why i didnt uploaded it as well.

Now, this happens when i hit play:

The wheels have no collision at all. Changing the radius of the vehicle wheel blueprint wont do anything.

When i delete all wheels inside the vehicle blueprint:


i get this result:

The plane wheels have now finally a collision, but of course its only the from the physic asset and no steering input can be applied to it. So the problem is definitly inside the vehiclewheel blueprint from the collision itself. Any ideas if this is an bug?

I too am suffering the same problem,

I am using the same version, and perhaps interestingly mine is also not your average 4 wheel vehicle ( six wheels/ axles)

Its either something we are missing or its deeper into the mysteries of UE4

Paul G

tbh guys, unless your just doing basic 4whl vehicle i’d leave it, the engine has some serious problems with the wheeled vehicle class due to physx stuff i believe, don’t hold your breath on the devs fixing it we’ve been waiting over 2 years for a fix.

you might want to have a look at this free plug-in, its complex but gets the job done afaik

Thanks for the reply, if it is caused by the “n” number of wheels then all is lost :slight_smile:
My own attempt has been to try to redesign my physics railvehicle (made with static meshes and constraints) as a “vehicle” using skeletal meshes and wheels.

So if physx works with static meshes it must be a UE4 vehicle problem?

My actor version with static meshes seen here

Paul G

ok to start with if you try the wheeled vehicle class then its really the 4wd so it will crash if you have more than 4 whls, ‘n’ whls is not an option from this class atm afaik

the physx wheel colision issue is known and works from skeletal meshes, how this would effect actors build with static meshs i can’t say, but from past tests if you just rotate the static then the colision mesh doesn’t rotate with it, afaik you need to apply torque for the col mesh to rotate, check Alan Noone’s tank tutorial.

i believe the physx issue is due to the line trace of the wheel colision eg checks on each revolution of the wheel, tbh its well beyoud me i just want to warn of issues before people get to deep into dev

It appears that I can confirm that (in my case ) it was the irregular number of wheels.
I have configured a test bogie vehicle using 4 wheels and have it working as a vehicle BP
(the wheels are not at the four corners as per normal but are of 2m width and lined up one behind the other.

So I guess this counts as a little progress :slight_smile:

Paul G

Yeah, I’ve been dealing with this problem myself. Haven’t had any success with a 2 wheeled motorcycle so I’m about to try making it with 4 wheels instead.