How does vehicle suspension work?

[juanc3112]

Hi guys, I wanted to modify a vehicle and make the suspension much more realistic, sometimes the suspension is hard and unrealistic as it looks like a piece of block without movement.
I need to know what each of these values ​​mean, I've been researching and testing but they don't look very good.
What does each of these options mean, what is each one for?

physics tipOcclusionAreaGroupId="1"
rotSpeed="1"
restLoad="0.2"
radius="0.51"
width="0.27"
forcePointRatio="0.5"
initialCompression="25"
suspTravel="0.9"
spring="5"
damper="2"
transRatio="1.5"
frictionScale="10"/>

Edit don_apple: topic moved from german to english section.

[OneAmongOthers]

Most of these vehicles (aside from pickups and semi trucks or trailers) have no suspension. Solid axles. It's the cab and seat that provide suspension for the driver.

[HatsuneKid]

You only need to adjust the values of [suspTravel] [spring] [damper] depending on the mass of the vehicle.
You can think of the suspension system as a spring.
[suspTravel] means compression distance of this spring.
[spring] means elasticity of spring.
[damper] means a resistance will be applied when the spring is compressed and rebounded. This reduces the jumping of the vehicle on bumpy roads.

[juanc3112]

Thank you very much, I have been able to improve a little. But the rear part when the wheels go through the vehicle, how can I fix it? I like the wheels to stretch downwards but I don't like them to go through the car upwards

[HatsuneKid]

Thank you very much, I have been able to improve a little. But the rear part when the wheels go through the vehicle, how can I fix it? I like the wheels to stretch downwards but I don't like them to go through the car upwards

I suggest you import the wheel model into the I3D file of the vehicle to observe.
First of all, you need to find out where the wheel is at the highest position if you don't want the wheel go through the vehicle.
For example, I found out that the wheel was attached to this node 0>0|1|0. The highest optimal position of this node is 0.74




Then move the node down to the most appropriate position I think. Maybe 0.54


0.74-0.54=0.2 Now this is the value of [suspTravel] I need.
And 0.54 is the node position which I need to save in i3d file means the original position of wheel. (Don't forget to delete the wheel model you just imported before saving)
Then you just need to adjust the values of [spring] and [damper].



Exceptions
Sometimes such code may appear in the XML file
<objectChange node="xxxxxxx" translationActive="x x x" translationInactive="x x x"/>
This may invalidate the node location you modified in I3D. Because the code in the XML file has higher priority, at this time you only need to change the node coordinate value in the XML.

[juanc3112]

Thank you, the information has helped me. One last question, is there a way to define the height to stretch up and down? The wheels no longer go through the vehicle, but they stretch very little downwards, do you know how I can improve that?

[HatsuneKid]

Thank you, the information has helped me. One last question, is there a way to define the height to stretch up and down? The wheels no longer go through the vehicle, but they stretch very little downwards, do you know how I can improve that?

I quote the example I gave above. I could move the node of the wheels down to 0.24 in i3d file. And increase the value of [suspTravel] to 0.5 in xml file.
In short, the position of wheel nodes in i3d file also represents the position when the wheel is stretched down the maximum distance. Based on this position, [susptravel] determines the maximum distance that the wheel is stretched upward, in meters.