Joining Soft Bodies in Ammo.js

When working with soft bodies in Ammo.js, joining two cloth pieces can be challenging. While appendLink() exists in the Bullet Physics documentation, implementing it correctly in Ammo.js requires some specific approaches.

Possible Solutions

There are a few approaches you might consider:

1. Using Anchors: Instead of directly linking two soft bodies, you can anchor specific points of both cloths to rigid bodies, and then constrain those rigid bodies together.

2. Manual Node Connection: You can try to manually connect nodes between the two soft bodies.

Here's a basic implementation example for connecting soft bodies:

JAVASCRIPTCopied
// Assuming you have two soft bodies already created: softBody1 and softBody2

// Get the nodes from both soft bodies
const numNodes1 = softBody1.get_m_nodes().size();
const numNodes2 = softBody2.get_m_nodes().size();

// Find nodes that should be connected (this depends on your geometry)
// For example, connecting edge nodes that are close to each other
for (let i = 0; i < numNodes1; i++) {
    const node1 = softBody1.get_m_nodes().at(i);
    
    for (let j = 0; j < numNodes2; j++) {
        const node2 = softBody2.get_m_nodes().at(j);
        
        // Calculate distance between nodes
        // This is a simplified example - you'll need to implement proper distance calculation
        const distance = calculateDistance(node1, node2);
        
        // If nodes are close enough, create a link
        if (distance < threshold) {
            // Create a link between the nodes
            // This is where you would use appendLink or an alternative
            softBody1.appendLink(node1, node2, material);
            // Or try alternative approaches if this doesn't work
        }
    }
}

Alternative Approaches

If direct linking doesn't work, consider:

1. Using a Single Soft Body: Instead of trying to join two separate soft bodies, you might model your cloth as a single soft body with varying properties.

2. Rigid Body Constraints: Create small invisible rigid bodies at the connection points and use constraints to join them.

3. Custom Forces: Apply custom forces to keep the edges of the two cloths together.

Remember that the exact implementation will depend on your specific use case and the version of Ammo.js you're using. You might need to experiment with different approaches to find what works best for your scenario.