Downforce on raycast suspension car

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#1

I currently have a car which uses raycast/scripted suspension to stay up and an AlignOrientation to orientate itself to the ground below. I have a problem where the car’s suspension raises when it’s driving over a hill at high speed.


Normally I would fix this using downforce; however doing so on what essentially is a floating brick brings it down by quite a lot, and I don’t know how to go around this. If there is any other way of preventing my issue from happening? I have tried manually clamping the car’s Y velocity based on its’ velocity in object space, however this does not seem to help.

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#2

Forgot to mention, but the only thing that seems to help this is maxing out the Gravity of Workspace, however that obviously comes with many downsides and I would prefer not to use this method.

#3

You need to multiply your damping vector by the raycast normal.

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#4

Already doing that. The issue does not come from the suspension itself, it’s just a natural physics occurence

#5

Interesting. Last time I checked, my raycast car does not have that issue. You can possibly try using a vector force to apply artificial gravity on the car.

#6

It just comes with speed, the car is travelling at a magnitude of ~300 and there isn’t enough gravity force pushing it down, if the ramp had been any sharper it would have just done a jump. I’m trying to find a way to apply downforce so that this doesn’t happen (obviously without messing up the suspension height)

#7

Pretty much what I’m trying to do, however adding a downwards force strong enough to counteract the forces causing the issue brings the car down, raycast suspension is pretty much a hovering script after all

#8

Alright. Is your raycast car using the normal for the lift force or just the global Y axis? I’ve used mine with the Y axis and it seemed to have this issue before I changed it to the normal of the raycast.

#9

Here is the spring code:

local springDir = sray.Normal
local worldVelocity = car:GetVelocityAtPosition(v.WorldPosition)

local rayDistance = (v.WorldPosition - sray.Position).Magnitude
local offset = (springLength - rayDistance)

local velocity = springDir:Dot(worldVelocity)
local force = (offset * stiffness) - (velocity * damping)

v.Spring.Force = springDir * force
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#10

What exactly is the value of damping? This code seems fine.

#11

Stiffness divided by 10, the code is fine

#12

Alright. What happens if you apply force relative to the raycast intersection position instead of relative to the car?

#13

If you mean raycast.Position the car just flings, if I multiply Force by Vector3.new(0,1,0), the suspension only works on straight/non-angled surfaces.

#14

Interesting. Does making it relative to the wheel have any different results?

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#15

Nope, nothing changes, issue still present

#16

Very weird. In my car, I just reduced damping and it seemed to fix that problem. You could try taking the dot product of the normal and the car’s velocity to calculate some sort of downforce.

#17

Did you try making your car go at around 300 speed?

#18

My car goes about that fast. However, to go those speeds the damping needs to be quite low so it doesn’t glitch out.

#19

Mine uses a BodyGyro to orientate itself, so I’m guessing this happens because the gyro doesn’t keep up when the car is going that fast

#20

This is most likely the case seeing as this issue only occurs at high speeds