Havok Spring Joints?

Questions
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3

How would a code look like for a simulation of a spring joint?

Here’s an example of how a simple simulation of a spring joint could be implemented using a physics engine like Havok. This code assumes you have a basic understanding of using Havok or a similar physics engine in your programming language of choice. Keep in mind that this is a simplified example and may require adjustments based on your specific implementation and requirements.

// Assume you have two rigid bodies, bodyA and bodyB, that you want to connect with a spring joint

// Create bodies and initialize their positions, velocities, and other properties
RigidBody bodyA, bodyB;
bodyA.SetPosition(Vector3(0.0f, 0.0f, 0.0f));
bodyB.SetPosition(Vector3(1.0f, 0.0f, 0.0f));

// Define spring properties
float springConstant = 100.0f;     // Stiffness of the spring
float dampingFactor = 0.5f;        // Damping coefficient

// Update loop (simulation step)
while (simulationRunning) {
    // Calculate the spring force
    Vector3 springForce = (bodyB.GetPosition() - bodyA.GetPosition()) * springConstant;

    // Calculate the relative velocity between the bodies
    Vector3 relativeVelocity = bodyB.GetVelocity() - bodyA.GetVelocity();

    // Apply damping to the relative velocity
    Vector3 dampingForce = relativeVelocity * dampingFactor;

    // Calculate the total force applied on bodyA and bodyB
    Vector3 totalForceOnA = springForce - dampingForce;
    Vector3 totalForceOnB = -springForce - dampingForce;

    // Apply the forces to the bodies
    bodyA.ApplyForce(totalForceOnA);
    bodyB.ApplyForce(totalForceOnB);

    // Step the physics simulation (e.g., using Havok's update function)
    physicsWorld.Update(timeStep);
}

In this example, the spring force is calculated as the displacement between the two bodies (bodyB’s position minus bodyA’s position) multiplied by the spring constant. The relative velocity between the bodies is obtained by subtracting bodyA’s velocity from bodyB’s velocity. Damping force is then calculated by multiplying the relative velocity by a damping factor. The total forces are applied to the bodies using the ApplyForce function provided by Havok or your chosen physics engine.

Remember that this is just a basic example, and you may need to consider additional factors such as mass, time integration, collision handling, and more to create a more accurate and robust simulation.

I hope this gives you enough input to create a spring joint in bb! :slight_smile:

More input about joints:
Havok set joints positions on Raycast - Questions - Babylon.js (babylonjs.com)