add_joint
Connect two rigid bodies with a joint constraint, choosing from fixed, revolute, spherical, or prismatic types to control motion.
Instructions
Add a joint/constraint to connect two rigid bodies.
Joints allow you to constrain the motion between bodies:
- FIXED: Rigid connection (glue objects together)
- REVOLUTE: Hinge rotation around an axis (doors, pendulums)
- SPHERICAL: Ball-and-socket rotation (ragdolls, gimbals)
- PRISMATIC: Sliding along an axis (pistons, elevators)
Args:
sim_id: Simulation identifier
joint: Joint definition with type and parameters
Returns:
joint_id: Unique identifier for the created joint
Example - Simple Pendulum:
# Create fixed anchor point
add_rigid_body(
sim_id=sim_id,
body_id="anchor",
body_type="static",
shape="sphere",
size=[0.05],
position=[0.0, 5.0, 0.0],
)
# Create pendulum bob
add_rigid_body(
sim_id=sim_id,
body_id="bob",
body_type="dynamic",
shape="sphere",
size=[0.1],
mass=1.0,
position=[0.0, 3.0, 0.0],
)
# Connect with revolute joint (hinge)
add_joint(
sim_id=sim_id,
joint=JointDefinition(
id="pendulum_joint",
joint_type="revolute",
body_a="anchor",
body_b="bob",
anchor_a=[0.0, 0.0, 0.0], # Center of anchor
anchor_b=[0.0, 0.1, 0.0], # Top of bob
axis=[0.0, 0.0, 1.0], # Rotate around Z-axis
),
)Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| sim_id | Yes | ||
| joint | Yes | Definition for creating a joint between two bodies. |