Bullet Vehicle

Controlling the Suspension

Getting the vehicles to rest properly on the ground is hard.

Recommended settings:

Length should be whatever distance from wheel center to maximum shock compression.

Stiffness: ~500

Damping Relaxation: ~500

Damping Compression: 1.0

Max Travel: ~30

Max Force: ~100

Wheel Axes

Rotation Axis is the axis around which the wheel spins.

All wheels should be aligned the same as the Front Left wheel.

If X+ is pointing OUT of the Front Left wheel, then the Rotation Axis is X+

Suspension Axis is the direction the vehicle travels (e.g. forward relative to the vehicle body).

So if the Y+ axis points out the front of the vehicle, then the Suspension Axis is Y+

Vehicle Hierarchy

Remember when creating vehicles for BT Vehicle that the wheels must be linked to the body in a SPECIFIC ORDER!

Front Left

Front Right

Rear Left

Rear Right

These notes are rather old...

1. To create the car, create the body geo and link some wheels to it.

wheel order matters: front left, front right, back left, back right

2. Create a particle group called car (or whatever, this is to hold the top-level entity of the vehicle), and create sub-groups for body and wheels

3. Create an SC collision operator

4. Born the body particles with any basic generator method (PosBorn, MW, Draw, etc)

be careful if trying Obj2Particle that it might upset the orientation

5. Create the first Vehicle operator and use the body as the Particle input

of course be sure to set the "Collision" parameter at the top of the operator to the Collision operator in your tree

setup the initial Vehicle properties (dampening, axes, etc)

6. Create the second Vehicle operator

tell it to use the same Collision operator

create a body particle input

assign the same G Body and G Wheel settings as the first Vehicle operator

control the Speed and Steering and other inputs with this second Vehicle operator

Note: the original mesh transform may affect the alignment of the top-level "car" group -- use Set Alignment to handle any corrections (on birth only).

Note: Spin may screw up the wheels and cause them to spin around the body

Note: Dampers (or shocks) are straight

Damper Height is the height between the body and the wheel center

Damper Spring: is the spring constant (hardness)

Spring Damper: is the dampening progressiveness or friction so it stops springing

Spring Damper=0 means it swings forever