Hi everyone , I am a new beginner at Isaac Sim. I try to dynamic crate a 3d model to my scene, but every time I create it, the terminal shows the following picture error. I don’t know how to fix it. I used create_prim function to make it, is that a wrong way?
would you please provide more details and explain your steps
The following is my code:
# Copyright (c) 2020-2021, NVIDIA CORPORATION. All rights reserved.
#
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# and proprietary rights in and to this software, related documentation
# and any modifications thereto. Any use, reproduction, disclosure or
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# license agreement from NVIDIA CORPORATION is strictly prohibited.
from omni.isaac.examples.base_sample import BaseSample
from omni.isaac.core.objects import DynamicCuboid
from omni.isaac.core.utils.nucleus import find_nucleus_server
from omni.isaac.core.utils.stage import add_reference_to_stage
from omni.isaac.core.robots import Robot
from omni.isaac.core.utils.types import ArticulationAction
from omni.isaac.core.controllers import BaseController
from omni.isaac.core.utils.prims import create_prim
from omni.isaac.core.utils.prims import delete_prim
from omni.isaac.core.utils.rotations import euler_angles_to_quat
from omni.isaac.core.articulations import Articulation
from pxr import Usd, UsdLux, UsdGeom, Sdf, Gf, Tf, UsdPhysics
from omni.usd import get_context
from omni.physx.scripts import utils
# This extension includes several generic controllers that could be used with multiple robots
import carb
import numpy as np
import time
import math
from pxr import UsdPhysics
import omni
import socket , pickle
import threading
import asyncio
from omni.isaac.dynamic_control import _dynamic_control
from scipy.spatial.transform import Rotation
import copy
class TMController(BaseController):
def __init__(self):
super().__init__(name="TM_controller")
# An open loop controller that uses a unicycle model
print('controller initial success')
return
def forward(self,joint_positions):
# A controller has to return an ArticulationAction
#joint_positions = np.random.rand(6)
print('Move by socket pos')
return ArticulationAction(joint_positions = joint_positions)
class HelloWorld(BaseSample):
def __init__(self) -> None:
super().__init__()
self._widget_index = 1
self._dc = _dynamic_control.acquire_dynamic_control_interface()
self._linearDriveAPI = []
self._prismaticJoint = []
self._conveyor = []
self._pos = [0,130,250,380,490,620]
self._run_index = 0
return
def setup_scene(self):
world = self.get_world()
add_reference_to_stage(usd_path="/home/quanta/Desktop/WorkingCopy/Robots/Collected_Conveyor0/Conveyor0.usd", prim_path="/Group")
for i in range(7):
cv = Conveyor()
cv.ConveyorNo = i+1
self._conveyor.append(cv)
return
async def setup_post_load(self):
self._world = self.get_world()
self._controller = TMController()
self._world.add_physics_callback("sim_step", callback_fn=self.physics_step)
#------articulation controller---------
self._conveyorThread = threading.Thread(target=self.DepolyPalet,args=())
return
def DepolyPalet(self):
while True:
if self._conveyor[0].carrier == None:
_thread = threading.Thread(target=asyncio.run, args=(self.AddPlate_aync(),))
_thread.start()
#_thread.join()
time.sleep(1)
#await asyncio.sleep(1)
return
async def setup_pre_reset(self):
return
async def setup_post_reset(self):
self._controller.reset()
await self._world.play_async()
return
def world_cleanup(self):
return
def physics_step(self, step_size):
if self._dc.is_simulating():
for i in range(len(self._conveyor)):
if i < len(self._conveyor) -2:
if(self._conveyor[i+1].carrier == None and self._conveyor[i].carrier != None and self._conveyor[i].carrier.status == 1):
self._conveyor[i].carrier.status = 0
self._conveyor[i+1].carrier = copy.copy(self._conveyor[i].carrier)
_thread = threading.Thread(target=self.MovePallet, args=(i,))
_thread.start()
return
def MovePallet(self,posIndex):
car = Articulation(prim_path= self._conveyor[posIndex].carrier.carrier_Name)
target = car.get_world_pose()[0][1] - (self._pos[posIndex+1] - self._pos[posIndex])
self._conveyor[posIndex].carrier.linearDriveAPI.CreateTargetPositionAttr(self._pos[posIndex+1])
count = 0
while True:
current = car.get_world_pose()[0][1]
print("Target Pos:",target,"Current:",current)
if math.fabs(target - current) < 8 and math.fabs(target - current) > 0:
self._conveyor[posIndex].status = 0
break
time.sleep(0.5)
count = count + 1
if count > 5:
self._conveyor[posIndex].carrier.linearDriveAPI.CreateTargetPositionAttr(self._pos[posIndex+1])
print("Reforce To Move")
count = 0
self._conveyor[posIndex].carrier =None
self._conveyor[posIndex+1].status = 1
time.sleep(0.5)
self._conveyor[posIndex+1].carrier.status = 1
return
async def _on_AddPlate_button_event_aync(self):
self._linearDriveAPI.clear()
platePath = '/Group/Carrier_{num:02d}'.format(num=self._widget_index)
rot = Rotation.from_euler('xyz', [0.7071, -0.7071, 0], degrees=True)
rot_quat = rot.as_quat()
create_prim(prim_path=platePath,#"/Group/Carrier_01",
prim_type="Xform",
position = np.array([77.6384, 63.1789, -178.758]),
scale=np.array([1,1,1]),
#orientation=euler_angles_to_quat(np.array([1.5707346, 0, -1.5707346])),#rot_quat,#np.array([90, -90, 0])#
usd_path="//home/quanta/Desktop/WorkingCopy/Robots/Carrier2.usd",
)
#jointPath = '/Group/Conveyor_01/StartPos/prismaticJoint_{num:02d}'.format(num=self._widget_index)# {self._widget_index:02d}"
jointPath = platePath+'/prismaticJoint_{num:02d}'.format(num=self._widget_index)
stage = get_context().get_stage()
prismaticJoint = UsdPhysics.PrismaticJoint.Define(stage, jointPath)
prismaticJoint.CreateAxisAttr("X")
prismaticJoint.CreateBody0Rel().SetTargets(["/Group/Conveyor_01/StartPos"])
prismaticJoint.CreateBody1Rel().SetTargets([platePath])
prismaticJoint.CreateLocalPos0Attr().Set(Gf.Vec3f(33.90559, -80.13061, 9.248482))
prismaticJoint.CreateLocalRot0Attr().Set(Gf.Quatf(0.707,0,-0.707,0))
self._prismaticJoint.append(prismaticJoint)
print("Prismaticjoint:",len(self._prismaticJoint))
# add linear drive
linearDriveAPI = UsdPhysics.DriveAPI.Apply(stage.GetPrimAtPath(jointPath), "linear")
linearDriveAPI.CreateTypeAttr("force")
linearDriveAPI.CreateMaxForceAttr(10000000000)
linearDriveAPI.CreateTargetVelocityAttr(0)
linearDriveAPI.CreateTargetPositionAttr(0)
linearDriveAPI.CreateDampingAttr(8000000.0)
linearDriveAPI.CreateStiffnessAttr(10000000.0)
#prismaticJoint.CreateLocalPos0Attr().Set(Gf.Vec3f(77.9125, 66.4155, -178.664))
self._linearDriveAPI.append(linearDriveAPI)
self._widget_index +=1
return
async def AddPlate_aync(self):
platePath = '/Group/Carrier_{num:02d}'.format(num=self._widget_index)
create_prim(prim_path=platePath,#"/Group/Carrier_01",
prim_type="Xform",
position = np.array([77.6384, 63.1789, -178.758]),
scale=np.array([1,1,1]),
#orientation=euler_angles_to_quat(np.array([1.5707346, 0, -1.5707346])),#rot_quat,#np.array([90, -90, 0])#
usd_path="//home/quanta/Desktop/WorkingCopy/Robots/Carrier2.usd",
)
jointPath = platePath+'/prismaticJoint_{num:02d}'.format(num=self._widget_index)
stage = get_context().get_stage()
prismaticJoint = UsdPhysics.PrismaticJoint.Define(stage, jointPath)
prismaticJoint.CreateAxisAttr("X")
prismaticJoint.CreateBody0Rel().SetTargets(["/Group/Conveyor_01/StartPos"])
prismaticJoint.CreateBody1Rel().SetTargets([platePath])
prismaticJoint.CreateLocalPos0Attr().Set(Gf.Vec3f(33.90559, -80.13061, 9.248482))
prismaticJoint.CreateLocalRot0Attr().Set(Gf.Quatf(0.707,0,-0.707,0))
self._prismaticJoint.append(prismaticJoint)
print("Prismaticjoint:",len(self._prismaticJoint))
# add linear drive
linearDriveAPI = UsdPhysics.DriveAPI.Apply(stage.GetPrimAtPath(jointPath), "linear")
linearDriveAPI.CreateTypeAttr("force")
linearDriveAPI.CreateMaxForceAttr(10000000000)
linearDriveAPI.CreateTargetVelocityAttr(0)
linearDriveAPI.CreateTargetPositionAttr(0)
linearDriveAPI.CreateDampingAttr(8000000.0)
linearDriveAPI.CreateStiffnessAttr(10000000.0)
pallet = Pallet()
pallet.carrier_Name = platePath
pallet.jointPath = jointPath
pallet.joint_Name = 'prismaticJoint_{num:02d}'.format(num=self._widget_index)
pallet.prismaticJoint = prismaticJoint
pallet.linearDriveAPI = linearDriveAPI
pallet.status = 1
self._conveyor[0].carrier = pallet
self._conveyor[0].status = 1
self._widget_index +=1
return
async def _on_DelPlate_button_event_aync(self):
delete_prim(prim_path='/Group/Carrier_{num:02d}'.format(num=self._widget_index-1))
delete_prim(prim_path='/Group/Conveyor_01/StartPos/prismaticJoint_{num:02d}'.format(num=self._widget_index-1))
self._linearDriveAPI.pop(0)
return
async def _on_Move_button_event_aync(self):
pos = [130,250,380,490,620]
self._linearDriveAPI[0].CreateTargetPositionAttr(pos[self._run_index])
print("Move to position:",pos[self._run_index])
self._run_index += 1
if self._run_index == len(pos):
self._run_index = 0
return
async def _on_Pause_button_event_aync(self):
return
async def _on_Stop_button_event_aync(self):
self._conveyorThread.start()
return
class Pallet:
def __init__(self, ):
self.status = 0 # 0:Idel 1:Finish
self.carrier_Name = "" # carrier name
self.jointPath = ""
self.joint_Name = ""
self.prismaticJoint = None
self.linearDriveAPI = None
self.PosNo = 0 # in which conveyor
class Conveyor:
def __init__(self,):
self.carrier = None
self.carrier_type = 0 # 0: crater 1:sled
self.status = 0 # 0:empty 1:have item
self.ConveyorNo = -1
The following link is the video
IsaacSim Dynamic add
pxr Usd API is not meant for async authoring. Whenever creating or modifying values in the USD, you need to make it in the main thread, so you can modify your async calls to set a flag, and then have the USD updated in the main loop by consuming that flag.
Thanks for your answer Rgasoto. But I still not sure where is the main loop in Isaac Sim’s framework. Could you demonstrate an example for me and other users to know the main loop in Isaac Sim. Thank you!
In your code, the main loop would be in function physics_step. Alternatively, you can sync up with the viewport update by subscribing to the timeline step:
def setup(self): #function where you set up your scene
self._app_update_sub = (
omni.kit.app.get_app().get_update_event_stream().create_subscription_to_pop(self._on_update_ui)
)
def _on_update_ui(self, step):
do_stuff()
Thank you Rgasoto, best regards to you!!
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