Physics Server

RapierPhysicsServer2D and RapierPhysicsServer3D extend Godot's physics servers with the methods below. Everything works on plain Godot nodes; the body and joint nodes are inspector conveniences over this API.

All methods are static: RapierPhysicsServer2D.method(...). The 3D server has the same API with 3D types.

Body parameters

RapierPhysicsServer2D.body_set_extra_param(rid, param, value)
RapierPhysicsServer2D.body_get_extra_param(rid, param)

Constant	Value	Type
`BODY_PARAM_CONTACT_SKIN`	0	`float`
`BODY_PARAM_DOMINANCE`	1	`int`
`BODY_PARAM_SOFT_CCD`	2	`float`
`BODY_PARAM_MASSLESS`	3	`bool`
`BODY_PARAM_ADDITIONAL_SOLVER_ITERATIONS`	4	`int`

See Body Nodes for what each does.

Contact queries

Method	Returns
`body_set_contact_force_threshold(body, threshold)`	Contact force a contact must exceed before it is reported.
`body_get_contact_force_threshold(body)`	The threshold above.
`body_get_total_contact_impulse(body)`	Total contact impulse on the body this step, as a vector.
`body_get_max_contact_impulse(body)`	Strongest single contact impulse magnitude this step.
`body_get_total_friction_impulse(body)`	Total friction impulse magnitude this step.
`body_get_contact_tangent_impulse(body, contact_idx)`	Friction impulse at one reported contact.
`bodies_get_contact_impulse(body_a, body_b)`	Impulse `body_a` receives from `body_b` specifically.

Impulses are read straight from the solver. Divide by the step delta for a force.

Body state

Method	Returns
`body_get_kinetic_energy(body)`	Kinetic energy combining linear and angular motion.
`body_is_ccd_active(body)`	Whether continuous collision detection actually ran for this body last step.

Joints

Create a joint with PhysicsServer2D.joint_create(), then shape it:

# Rope: bodies move freely while closer than max_distance.
RapierPhysicsServer2D.joint_make_rope(joint, anchor_a, anchor_b, max_distance, body_a, body_b)

# Fixed: locks all relative motion.
RapierPhysicsServer2D.joint_make_fixed(joint, anchor, body_a, body_b)

Anchors are in world space.

Joint parameters

RapierPhysicsServer2D.joint_set_extra_param(joint, param, value)
RapierPhysicsServer2D.joint_get_extra_param(joint, param)

Constant	Value	Meaning
`JOINT_TYPE`	0	The parameter selecting impulse vs multibody.
`JOINT_TYPE_IMPULSE_JOINT`	0	Solved iteratively by constraints.
`JOINT_TYPE_MULTIBODY_JOINT`	1	Solved exactly in reduced coordinates; cannot drift.
`JOINT_TYPE_MULTIBODY_KINEMATIC_JOINT`	2	Multibody with a kinematic root.

Tuning

Method	What it does
`joint_set_softness(joint, natural_frequency, damping_ratio)`	How rigidly the joint holds; damping ratio 1 is critically damped.
`joint_set_enabled(joint, enabled)`	Toggle without destroying: breakable constraints.
`joint_set_motor_position_options(joint, target_pos, stiffness, damping, enabled)`	Drive the joint to an angle like a spring. See motor position targets.

Reading forces

Method	Returns
`joint_get_reaction_impulse(joint)`	World-space linear impulse the joint applied last step.
`joint_get_reaction_angular_impulse(joint)`	World-space angular impulse last step.

Useful for breakable joints and rope tension. Multibody joints return zero.

Inverse kinematics

For multibody joints only. See Multibody Joints and IK.

Method	What it does
`joint_solve_inverse_kinematics(joint, target_transform)`	Solve the chain towards a target and apply the result.
`joint_set_ik_options(joint, damping, max_iterations, constrained_axes, epsilon_linear, epsilon_angular)`	Custom solver options for one joint.
`joint_reset_ik_options(joint)`	Back to Rapier defaults.

Fluids

Backing API of the fluid nodes. RIDs come from fluid_create().

Method	What it does
`fluid_create()`	Create a fluid, returns its RID.
`fluid_set_space(fluid, space)`	Put the fluid in a space.
`fluid_set_density(fluid, density)`	Set density.
`fluid_set_effects(fluid, effects)`	Set effect resources (viscosity, elasticity, surface tension).
`fluid_set_points(fluid, points)`	Replace all particles.
`fluid_set_points_and_velocities(fluid, points, velocities)`	Replace particles and velocities.
`fluid_add_points_and_velocities(fluid, points, velocities)`	Add particles.
`fluid_delete_points(fluid, indices)`	Remove particles by index.
`fluid_get_points(fluid)`	Particle positions.
`fluid_get_velocities(fluid)`	Particle velocities.
`fluid_get_accelerations(fluid)`	Particle accelerations.
`fluid_get_particles_in_aabb(fluid, aabb)`	Indices of particles inside a box.
`fluid_get_particles_in_ball(fluid, center, radius)`	Indices of particles inside a sphere.
`fluid_set_collision_masks(fluid, mask, layer)`	Interaction groups.
`fluid_get_collision_mask(fluid)` / `fluid_get_collision_layer(fluid)`	Read them back.

Spaces and stepping

Method	What it does
`space_step(space, delta)`	Step one space manually. Requires disabling automatic stepping.
`space_flush_queries(space)`	Flush queued callbacks after `space_step`.
`space_get_active_bodies(space)`	RIDs of the active bodies.
`space_get_bodies_transform(space, bodies)`	Transforms for a list of bodies.

Identity and diagnostics

Method	What it does
`get_rapier_id(rid)`	Stable id of an object; survives scene reload, used with serialization.
`get_global_id()` / `set_global_id(id)`	The server's id counter; restore it when loading a saved state.
`get_stats()`	Dictionary of internal counters.

State saving

Exporting and importing whole-space state lives on the RapierStateManager2D / RapierStateManager3D nodes, not the server. See Serialization.

Physics Server

Body parameters​

Contact queries​

Body state​

Joints​

Joint parameters​

Tuning​

Reading forces​

Inverse kinematics​

Fluids​

Spaces and stepping​

Identity and diagnostics​

State saving​