Is there a way to get the collision point of a RigidBody3D?

Help Physics
,
1

Godot Version

4.2

Question

Is there a way to get the collision point between a RigidBody3D and another PhysicsBody3D?

2

Yes. You can get the contact point(s) of a RigidBody3D via a reference to its state (PhysicsDirectBodyState3D).

The state of a Rigidbody3D can be obtained either through _integrate_forces() where the state is a parameter, or by requesting it from the physics server (PhysicsServer3D).

Once obtained, you can retrieve contact information from the state via various methods. Here is an example:

 func _integrate_forces(state):
    var contact_point = state.get_contact_collider_position(0)

Note that a contact_index is required as an input since a physics body can either be in contact with several objects at once, or in contact with the same object in multiple places.

If you wish to get the contact point for a specific object, you first have to determine which contact index relates to that object. One way of doing this is to compare the RID of your other body to that of every contact body.

var target_body_id: RID   # This would be the RID of your other PhysicsBody3D

var target_contact_idx = -1  # The contact index for your target body
var contacts = state.get_contact_count()
for i in range(contacts):
    var id = state.get_contact_collider(i)
    if id == target_body_id:
        target_contact_idx = id
        break

IMPORTANT: In order to retrieve contact information, the physics body you’re using (RigidBody3D) must have it’s contact monitor set up correctly. This means setting contact_monitor to true and setting max_contacts_reported to a value above 0.

Hopefully, this helps you tackle your problem. Let me know if there is anything you need help with.

Relevant resources:

1 Like