Simulation for Forklift

Omniverse Isaac Sim
1

While going through the documentation, i was able to replicate the amr_navigation.py for my forklift, but right now the path is random and i want my forklift/carter to move to the point i want for that i created an empty Xform and placed in the scene and the translate were x = -24, y = 0, z=0. but i am unable to move it to that point, It would be great if you could help me with this and even suggest changes in my code.

NOTE:-

# *** Run the code, fix camera positions in viewport, press ENTER in terminal to start recording ***

“”“Generate offline synthetic dataset with Carter NAV movement”“”

import argparse

import json

import math

import os

import random

import threading

import yaml

from isaacsim import SimulationApp

config = {

"launch_config": {

    "renderer": "RaytracedLighting",

    "headless": False,

},

"resolution": \[1920, 1080\],

"rt_subframes": 4,

"num_frames": 800,

"env_url": "/Isaac/Environments/Simple_Warehouse/full_warehouse.usd",

"writer": "BasicWriter",

"writer_config": {

    "output_dir": "\_out_custom_sdg_forklift",

    "rgb": True,

    "bounding_box_2d_tight": True,

    "semantic_segmentation": True,

    "bounding_box_3d": True,

    "occlusion": True,

},

"clear_previous_semantics": True,

"forklift": {

    "url": "/Isaac/Props/Forklift/forklift.usd",

    "class": "forklift",

},

"cone": {

    "url": "/Isaac/Environments/Simple_Warehouse/Props/S_TrafficCone.usd",

    "class": "traffic_cone",

},

"pallet": {

    "url": "/Isaac/Environments/Simple_Warehouse/Props/SM_PaletteA_01.usd",

    "class": "pallet",

},

"cardbox": {

    "url": "/Isaac/Environments/Simple_Warehouse/Props/SM_CardBoxD_04.usd",

    "class": "cardbox",

},

"close_app_after_run": True,

}

import carb

parser = argparse.ArgumentParser()

parser.add_argument(“–config”, required=False, help=“Include specific config parameters (json or yaml)”)

args, unknown = parser.parse_known_args()

args_config = {}

if args.config and os.path.isfile(args.config):

print("File exist")

with open(args.config, "r") as f:

    if args.config.endswith(".json"):

        args_config = json.load(f)

    elif args.config.endswith(".yaml"):

        args_config = yaml.safe_load(f)

    else:

        carb.log_warn(f"File {args.config} is not json or yaml, will use default config")

else:

if args.config:

    carb.log_warn(f"File {args.config} does not exist, will use default config")

if “writer_config” in args_config:

config\["writer_config"\].clear()

config.update(args_config)

simulation_app = SimulationApp(launch_config=config[“launch_config”])

import carb.settings

import omni.replicator.core as rep

import omni.usd

import omni.timeline

import scene_based_sdg_utils

from isaacsim.core.utils import prims

from isaacsim.core.utils.rotations import euler_angles_to_quat

from isaacsim.core.utils.stage import get_current_stage, open_stage

from isaacsim.core.utils.stage import add_reference_to_stage

from isaacsim.storage.native import get_assets_root_path

from pxr import Gf, UsdGeom, UsdPhysics, PhysxSchema

assets_root_path = get_assets_root_path()

if assets_root_path is None:

carb.log_error("Could not get nucleus server path, closing application..")

simulation_app.close()

print(f"[scene_based_sdg] Loading Stage {config[‘env_url’]}")

if not open_stage(assets_root_path + config[“env_url”]):

carb.log_error(f"Could not open stage {config\['env_url'\]}, closing application..")

simulation_app.close()

rep.orchestrator.set_capture_on_play(False)

carb.settings.get_settings().set(“rtx/post/dlss/execMode”, 0)

stage = get_current_stage()

if config[“clear_previous_semantics”]:

scene_based_sdg_utils.remove_previous_semantics(stage)

# ================================================================

# ✅ COLLISION FIX

# ================================================================

physics_scene_path = “/physicsScene”

if not stage.GetPrimAtPath(physics_scene_path).IsValid():

physics_scene = UsdPhysics.Scene.Define(stage, physics_scene_path)

physx_scene   = PhysxSchema.PhysxSceneAPI.Apply(stage.GetPrimAtPath(physics_scene_path))

physx_scene.GetEnableCCDAttr().Set(True)

physx_scene.GetEnableGPUDynamicsAttr().Set(False)

physx_scene.GetBroadphaseTypeAttr().Set("MBP")

print("\[scene_based_sdg\] Physics scene with CCD + MBP created.")

else:

physx_scene = PhysxSchema.PhysxSceneAPI.Apply(stage.GetPrimAtPath(physics_scene_path))

physx_scene.GetEnableCCDAttr().Set(True)

physx_scene.GetEnableGPUDynamicsAttr().Set(False)

physx_scene.GetBroadphaseTypeAttr().Set("MBP")

print("\[scene_based_sdg\] Physics scene patched with CCD + MBP.")

# ================================================================

# CARTER NAV

# ================================================================

add_reference_to_stage(

usd_path=assets_root_path + "/Isaac/Samples/Replicator/OmniGraph/nova_carter_nav_only.usd",

prim_path="/NavWorld/CarterNav"

)

# ================================================================

# FORKLIFT WRAPPER

# ================================================================

wrapper_path = “/NavWorld/CarterNav/chassis_link/ForkliftWrapper”

forklift_path = wrapper_path + “/Forklift”

wrapper_prim = stage.DefinePrim(wrapper_path, “Xform”)

add_reference_to_stage(

usd_path=assets_root_path + config\["forklift"\]\["url"\],

prim_path=forklift_path

)

wrapper_xform = UsdGeom.Xformable(wrapper_prim)

wrapper_xform.ClearXformOpOrder()

wrapper_xform.AddOrientOp().Set(Gf.Quatf(0.707, Gf.Vec3f(0, 0, 0.707)))

# ================================================================

# HIDE CARTER VISUALS

# ================================================================

carter_visual = stage.GetPrimAtPath(“/NavWorld/CarterNav/chassis_link/visuals”)

if carter_visual and carter_visual.HasAttribute(“visibility”):

carter_visual.GetAttribute("visibility").Set("invisible")

# ================================================================

# PALLET

# ================================================================

pallet_prim = prims.create_prim(

prim_path="/World/Pallet",

position=(0.0, -1.5, 0.0),

orientation=euler_angles_to_quat(\[0, 0, 0\]),

usd_path=assets_root_path + config\["pallet"\]\["url"\],

semantic_label=config\["pallet"\]\["class"\],

)

# ================================================================

# SEMANTIC LABEL ON FORKLIFT

# ================================================================

forklift_prim = stage.GetPrimAtPath(forklift_path)

if forklift_prim.IsValid():

try:

    from isaacsim.core.utils.semantics import add_update_semantics

    add_update_semantics(forklift_prim, config\["forklift"\]\["class"\])

except Exception:

    pass

foklift_pos_gf = Gf.Vec3d(0.0, 0.0, 0.0)

pallet_pos_gf = Gf.Vec3d(0.0, -1.5, 0.0)

# ================================================================

# REGISTER RANDOMIZATION GRAPHS

# ================================================================

scene_based_sdg_utils.register_scatter_boxes(pallet_prim, assets_root_path, config)

scene_based_sdg_utils.register_cone_placement(forklift_prim, assets_root_path, config)

scene_based_sdg_utils.register_lights_placement(forklift_prim, pallet_prim)

# ================================================================

# simulate_falling_objects BEFORE timeline.play()

# ================================================================

print(“[scene_based_sdg] Running falling objects simulation…”)

scene_based_sdg_utils.simulate_falling_objects(forklift_prim, assets_root_path, config)

print(“[scene_based_sdg] Falling objects done.”)

for _ in range(20):

simulation_app.update()

# ================================================================

# CAMERAS

# ================================================================

warehouse_cam_left = rep.create.camera(name=“WarehouseCamLeft”)

warehouse_cam_right = rep.create.camera(name=“WarehouseCamRight”)

with warehouse_cam_left:

rep.modify.pose(

    position=(-26.38117, -23.45436, 6.06221),

    rotation=(79.57776, 0.0, -34.79463)

)

with warehouse_cam_right:

rep.modify.pose(

    position=(5.23387, -19.65781, 6.58365),

    rotation=(77.64104, 0.0, 42.62757)

)

resolution = tuple(config[“resolution”])

warehouse_left_rp = rep.create.render_product(warehouse_cam_left, resolution, name=“WarehouseLeft”)

warehouse_right_rp = rep.create.render_product(warehouse_cam_right, resolution, name=“WarehouseRight”)

rps = [warehouse_left_rp, warehouse_right_rp]

for rp in rps:

rp.hydra_texture.set_updates_enabled(False)

# ================================================================

# START TIMELINE

# ================================================================

timeline = omni.timeline.get_timeline_interface()

timeline.play()

print(“[scene_based_sdg] Warming up Carter articulation (200 ticks)…”)

for _ in range(200):

simulation_app.update()

# ================================================================

# CARTER PRIM HANDLES

# ================================================================

nav_target = stage.GetPrimAtPath(“/NavWorld/CarterNav/targetXform”)

carter = stage.GetPrimAtPath(“/NavWorld/CarterNav/chassis_link”)

if not nav_target.IsValid():

carb.log_error("targetXform not found")

simulation_app.close()

# ================================================================

# SPEED BOOST

# ================================================================

try:

nav_prim = stage.GetPrimAtPath("/NavWorld/CarterNav")

for attr_name, val in \[

    ("maxSpeed",        20.0),

    ("maxAcceleration", 18.0),

    ("maxAngularSpeed", 200.0),

\]:

    attr = nav_prim.GetAttribute(attr_name)

    if attr and attr.IsValid():

        attr.Set(val)

print("\[scene_based_sdg\] Speed attributes set.")

except Exception as e:

print(f"\[scene_based_sdg\] Speed boost skipped: {e}")

# ================================================================

# FIXED DESTINATION NAVIGATION

# ================================================================

DESTINATION = (-24.79925, 0.0, 0.0)

# ================================================================

# INITIAL NAV TARGET

# ================================================================

nav_target.GetAttribute(“xformOp:translate”).Set(DESTINATION)

print(f"[scene_based_sdg] Moving Carter to destination: {DESTINATION}")

for _ in range(50):

simulation_app.update()

carter_pos = carter.GetAttribute(“xformOp:translate”).Get()

print(f"[scene_based_sdg] Carter position after init: {carter_pos}")

# ================================================================

# DISTANCE CHECK

# ================================================================

def distance_to_destination():

try:

    c = carter.GetAttribute("xformOp:translate").Get()



    if c is None:

        return 999.0



    return (

        (c\[0\] - DESTINATION\[0\]) \*\* 2 +

        (c\[1\] - DESTINATION\[1\]) \*\* 2

    ) \*\* 0.5



except Exception:

    return 999.0

# ================================================================

# CAMERA SETUP — press ENTER in terminal

# ================================================================

print(“\n” + “=”*60)

print(" CAMERA SETUP MODE")

print(" Carter + Forklift are moving in the viewport now")

print(" Adjust WarehouseCamLeft and WarehouseCamRight")

print(" → Press ENTER in terminal when ready to record")

print(“=”*60 + “\n”)

while simulation_app.is_running():

simulation_app.update()



try:

    import msvcrt

    if msvcrt.kbhit():

        key = msvcrt.getch()

        if key == b'\\r':

            break

except Exception:

    pass

print(“[scene_based_sdg] Starting SDG pipeline…”)

timeline.play()

for _ in range(50):

simulation_app.update()

# ================================================================

# WRITER SETUP

# ================================================================

if not os.path.isabs(config[“writer_config”][“output_dir”]):

config\["writer_config"\]\["output_dir"\] = os.path.join(

    os.getcwd(), config\["writer_config"\]\["output_dir"\]

)

print(f"[scene_based_sdg] Output directory = {config[‘writer_config’][‘output_dir’]}")

writer_type = config.get(“writer”, “BasicWriter”)

if writer_type not in rep.WriterRegistry.get_writers():

carb.log_error(f"Writer type {writer_type} not found")

simulation_app.close()

writer = rep.WriterRegistry.get(writer_type)

writer_kwargs = config[“writer_config”]

print(f"[scene_based_sdg] Initializing {writer_type} with: {writer_kwargs}")

writer.initialize(**writer_kwargs)

# ================================================================

# REPLICATOR TRIGGERS

# ================================================================

with rep.trigger.on_frame():

rep.randomizer.scatter_boxes()

rep.randomizer.randomize_lights()

with rep.trigger.on_custom_event(“randomize_cones”):

rep.randomizer.place_cones()

# ================================================================

# ENABLE RENDER PRODUCTS + ATTACH WRITER

# ================================================================

for rp in rps:

rp.hydra_texture.set_updates_enabled(True)

writer.attach(rps)

# ================================================================

# MAIN SDG LOOP

# ================================================================

rt_subframes = 1

num_frames = config.get(“num_frames”, 0)

print(f"[scene_based_sdg] Running SDG for {num_frames} frames")

for i in range(num_frames):

print(f"\[scene_based_sdg\] \\t Capturing frame {i}")



if i % 200 == 0:

    rep.utils.send_og_event(event_name="randomize_cones")



rep.orchestrator.step(

    delta_time=1/60,

    pause_timeline=False,

    rt_subframes=1

)

# ================================================================

# FINALISE

# ================================================================

rep.orchestrator.wait_until_complete()

writer.detach()

for rp in rps:

rp.destroy()

close_app_after_run = config.get(“close_app_after_run”, True)

if config[“launch_config”][“headless”]:

pass

elif not close_app_after_run:

print("\[scene_based_sdg\] App will stay open. Close manually.")



while simulation_app.is_running():

    simulation_app.update()

simulation_app.close()

2

Moving this to the Isaac Sim forum.