Hi again,
Thank you for your previous reply, it works perfectly. I am trying to figure out one thing and I really need your help. While I am setting the velocity in the forward direction, I would like the object’s rotation to remain locked. Additionally, I want to restrict its movement so that it can only translate along a single axis (the y-axis).
Is there a way to constrain the object so that its rotation is locked and its translation is limited to only one axis?
I have also added a visual representation what I want to do.
current code to enforce rotation:
def enforce_rotation():
while running:
vehicle1.sensors.poll()
pos = vehicle1.state\['pos'\]
vehicle1.teleport(pos=pos, rot_quat=(0, 0, 0, 1), reset=False)
time.sleep(0.05)
t = threading.Thread(target=enforce_rotation, daemon=True)
t.start()
Hello @SuvrangshuBarua,
BeamNGpy has no API to lock rotation or restrict motion to one axis. set_velocity pushes along the vehicle’s forward direction only — it does not fix orientation.
Important — axis convention
In BeamNG’s documented coordinate system (Nodes):
- X = left / right (lateral)
- Y = forward / back (longitudinal — this is the vehicle forward axis in JBeam)
- Z = up / down
So set_velocity moves the object along the vehicle’s local Y (forward), not X. If you want motion of your airbag along your “forward” in the diagram; you may rotate the airbag so its forward axis points along ±X:
If you must lock rotation
For a strict test rig (fixed orientation + motion on one axis only), you could teleport the object each simulation step:
vehicle.teleport((x, y0, z0), rot_quat=fixed_rot_quat, reset=False)
Keep y0 and z0 constant; only x changes.
Please let me know if you want help further help with your work!
Kind regards,
Abdulrahman Saeed
Research Software Engineer
BeamNG.tech Support Team
