The Spherecast wheels on Chaos vehicles seem to stick on and off of the sides of different objects when they make slight contact, almost like they’re magnetized.
They seem to magnetize towards other wheels as well, as you can see towards the end of the video, the car wheels are magnetizing upwards.
Is it possible to make it so they only stick downwards… to the ground?
https://www.youtube.com/watch?v=vpeZxCgI4yk
There’s no way wheel physics are this bad in 2026.
Well they basicly grab in to any possible object that gets near them no matter the direction(even up). There seems to be no magic fix to it as you can’t limit the direction. I hope im wrong and someone comes up with better solutions tho. In your example vehicle its even worse cause those tires are so slim. Sphere would be great whithout this issue.
If only the shapecast drop down option actually did anything. Perhaps the spherecast could have an area “masked out” so it knows better where to stick.
Sphere seems to be the only thing that keeps tires from falling in to tiny cracks. Line is basicly just a 1 line in the middle of the wheel always in same place and wheel will visually go trough objects untill it hits. Im not sure about shapecast ideology but yeah it does not sucks wheels in to objects and gives more accurate wheel contact points but still… its the worst of them all going trough the ground if there is a tiny gap. I guess its just how chaos is written and theres literally no way to block any hits from sphere. It is just a ball that grabs anything it is close to (expect your own car and this is why you cant block it with any sort of ucx logic. If unreal would fix this and the weird logic with differential where a tire has no torque if its counterpart is in air chaos would be very solid (it is very nice tho just these few issues to wrestle with).
I may be out of loop on the proceedings, as I’ve never heard of Spherecast Wheels, but the default offroad vehicle works just fine in my template (UE5.4.4). See below:
Sorry, if my response is off-topic. Though, if this has anything to do with trace channels, could you not just create a new one, which will only allow the terrain of your choosing to block it?
Also, I suspect your wheel size data is incorrect, based on how your wheels float.
The issue is that in your default vehicle you are using line trace. It works but it causes your wheel to clip in to objects untill that 1 line in the middle of your wheel hits the object and it snaps on top of it(its not issue if you dont have such objects on track) . It is the default option for your wheel trace. Then there is spherecast that basicly works very well on uneven surface using the “volume” of the sphere to look for edges. It looks very natural and good but there is big issue that it looks 360 degree around and basicly snaps in to any object your wheel is sitting next to… walls or if you turn that car upside down it tries to snap in to ground even the vehicle is upside down creating very buggy looking vehicle. Theres no way to limit the angle of the sphere reacting to the world. Ignoring objects would work but if your gonna drive on top of them its pretty bad fix. Then there is the 3rd option shapecast that would mostlikely work better but looking at the code it was never implimented and it just defaults as line trace so it seems like just empty button. Chaos vehicle without some heavy modification in source code works if your driving on flat surfaces or just dont care about your wheel clipping trough objects or falling trough 1 cm cracks. It kinda funny that chaos vehicle is great… then it has 2 options to choose from, either you want your wheel to clip trough objects or suck them self in to them like magnets (you can choose wich one you like more)
Okay, I found the settings you mentioned and tried a couple of things–Spherecast with simple sweep and with complex sweep. Neither resulted in issues; see below:
Spherecast and simple sweep:
Spherecast and complex sweep:
Again, apologies if I’m misunderstanding something; but the way the wheels seemed to vibrate in the original poster’s video suggest something’s wrong with the wheels themselves. I can only recommend verifying collision shape and size in the physics asset and wheel BP.
Once more with a larger cube–still Spherecast and complex sweep:
Thank you for helping folks out! You should be able to replicate the issue just by driving close to a wall and watching when the wheel starts to jitter between the ground and the wall. The more negative the angle is compared to the sphere, the worse the jitter becomes.
Also, turning your car upside down reveals the issue really fast. Even placing a cube above the tire will cause the system to ‘suck’ the tire in. In my example of being upside down, the sphere sucks the tire into the ground, completely bottoming out the suspension. This happens even when the sphere is much smaller than the wheel (the attached picture shows the wheel penetrating the ground).
This makes the system unusable for things like rough terrain—where it should actually shine—because the suspension literally grabs and pulls toward anything it sees instead of just supporting the vehicle’s weight
Edit: I remember seeing this being mentioned before and here is another good example of the issue some one posted few years ago Chaos Vehicle: Wheel Detecting Ground Upside down? - Programming & Scripting / Blueprint - Epic Developer Community Forums
Okay, I was able to recreate the issue next to a wall.
However, changing the collision type of the wall and the wheels’ response to the new collision type corrected the issue. See below that the right wall is ‘WorldStatic’, while I’ve changed the left to ‘WorldDynamic’ and set the VehMovComponent’s trace response to ignore ‘WorldDynamic’.
The left wall can be blocked without issue and only the right causes a problem.
I’ve not found a way to do this dynamically, but traditionally any setting (or most) on the right-hand menus can be changed in-game–if not with nodes, with C++ I imagine.
Thank you for having patience to test it out!
The issue arises when there are significant shifts in terrain height or objects you want to climb over, as well as when the car crashes and flips. In these scenarios, you can’t tag the objects correctly. While you could use Blueprints to stop the suspension from working when the vehicle is upside down, it wouldn’t effectively solve the root cause.
The core of the issue is hardcoded into ChaosWheeledVehicle.cpp sphere, so it isn’t accessible via C++ unless you fork the entire engine. The easiest solution would be for Epic to offer either multi-ray casting, a functional shapecast, or a function to limit the sphere angle. Since Chaos is an experimental plugin that was never fully completed, this is likely why these features are missing.
Bit of a late reply, had some issues to deal with over the week. Anyway.
The issue happens because the spherecast sticks the wheel to anything it makes contact with. So if you have a right angle object, high enough to make contact with the horizontal side of the sphere while the sphere is also touching the ground, the wheel bugs out because it’s trying to stick to both the object and the ground at the same time. With physics objects, the wheel sticking to them essentially applies force, kicking them out of the way.
In your video I saw the wheel glitching out a couple of times (like at 0:20 when you were testing with the big cubes), however you probably didn’t see it well as you kept driving past the items. You also have to make sure you’re driving close enough for the sphere to make proper contact. A lot of the items in your video were too low to the ground which prevents proper contact with the horizontal side of the sphere.
Lift the cubes up, get the wheels very close and try to stay still so you’ll see the sphere cast alternate between sticking to the object and the ground. It’s easier to see when you add physics simulation to those cubes and drive into them as I did in the video.
Having a bunch of low to the ground static objects won’t show you anything.
The world dynamic trick could come in handy for physics objects, however you’re basically removing the wheel interractions from the equation. So the wheels won’t realistically “climb” over objects. As for static objects, depending on what what kind of map you’re making and how your vehicle lands, the wheels will end up going through the ground.
Yeah, as @zonukka indicated, the limitations are likely from an incomplete system on UE’s part. Sorry, I couldn’t find a solution.
