Hey there, Epic team and Unreal community!
I recently tried out the UE4 vehicle component and decided to give some feedback. Overall it’s well made and kind of realistic. However, there are a few things that just aren’t enough for me.
- The friction system is unclear for me. It’s not enaugh with one stiffness value to define behaviour of wheel.
- Suspension doesn’t account for toe camber which are needed for both - tire behaviour and visual suspension effects.
- At neutral state engine RPM is 0. In real cars however, it is kept at around 1000 - 2000 RPM.
- There isn’t real automatic gearbox. The real automatic gearbox doesn’t have clutch, it also doesn’t switch to neutral gear during switching. Instead it’s “blending” between gears.
- There are no built in aerodynamical components except for drag so I have to set up all the wings manually.
My suggestions are:
- Add support for custom friction curves(x = slip, y = normalized force) and/or custom functions(normalized force = f(slip)).
- Add user adjustable camber and toe parameters. Also add user adjustable camber delta and toe delta values/curves/functions which controls the change of camber angle depending on compression of suspension. Make sure to apply the camber angle to the wheel bone.
- Calculate contact camber from surface normal and wheel’s up vector dot product(this gives cos so one more conversion needed). Use the angle as camber angle(y) for the friction calculations. Yeah, you need to take in camber angle.
- Make engine rev whenever it’s in neutral gear, but started and RPM is below user defined RPM rate.
- Just make realistic automatic gearbox model. Also add support for auto-clutch manual gearbox aswell as auto-switching manual(what you’ve got there currently).
- Add air density setting for control over drag. Add wing components which allows to set their position, direction, lift function. Than use simple angle of attack based equation to calculate the force which the wing uses to push car down or lift it up(or do whatever). This should be settable similar to gearbox gears(you can just click on + button to add new wing and X button to get rid of one).
I really hope that Epic team is interested in making their simulations accurate and advanced. Hopefully this all will be installed and in result UE4 will have one of the most advanced vehicle simulations ever seen in public game engines. I know that this is large and complex component, but it’s important to me and I’m ready to help in whatever way I can.