使用 NVIDIA Omniverse 构建 CAD 到 USD 工作流

./kit.exe `
--allow-root `
--enable omni.kit.converter.jt_core `
--exec `
--/app/fastShutdown=1 `
'"C:\Users\juslin\AppData\Local\ov\data\Kit\Justine_Composer\0.1\exts\3\omni.services.convert.cad-506.2.3+107.3.0.u353/omni/services/convert/cad/services/process/jt_main.py" --input-path "C:\Users\juslin\Downloads\Release2021.1Carterv2.0ASM.jt" --output-path "C:\Users\juslin\Downloads\NovaCarter.usd" --config-path "C:\Users\juslin\Downloads\jt_config.json"'`
--info

import omni.usd
import omni.kit.commands
import omni.scene.optimizer.core
import time
import json
import carb

# Get the UsdContext, which manages the application's scenes.
usd_context = omni.usd.get_context()
# Get the stage that is currently open in the application.
stage = usd_context.get_stage()

if not stage:
    carb.log_error("No stage is open. Please open your USD file first and run this script again.")
else:
    optimizer_interface = None
    try:
        # Get the optimizer interface.
        optimizer_interface = omni.scene.optimizer.core.acquire_interface()
        
        # Create the execution context.
        execution_context = omni.scene.optimizer.core.ExecutionContext()

        # Get the unique ID of the currently open stage.
        stage_id = usd_context.get_stage_id()
        execution_context.usdStageId = stage_id
        # -----------------------------------------

        # Define parameters.
        merge_params = {
            "merge_materials": True, 
            "merge_visuals_only": True
        }
       
        hidden_mesh_params = {
            "operation": "findHiddenMeshes",
            "paths": [],
            "gridResolution": 100.0,
            "action": 0, #This flag '0' sets the mesh to deactivate
            "useGpu": False
        }

        # Max mean error prevents the new mesh surface from deviating more than this amount from the original.
        decimation_params = {
            "decimation_filter_prim_type": "Mesh",
            "max_mean_error": 0.1 
        }

        carb.log_info("Context prepared. Executing operations...")

        # --- Execute Step 1: Merge Meshes ---
        carb.log_info("Running Step 1: Merge Meshes...")
        result = optimizer_interface.execute_operation("merge", execution_context, json.dumps(merge_params))
        
        if not result[0]:
            carb.log_error(f"Merge operation failed: {result[1]}")
        else:
            carb.log_info(f"Merge operation successful. Log: {result[1]}")

            # --- Execute Step 2: Find Hidden Meshes ---
            carb.log_info("Running Step 2: Find Hidden Meshes...")
            result = optimizer_interface.execute_operation("findHiddenMeshes", execution_context, json.dumps(hidden_mesh_params))
            
            if not result[0]:
                print("Find hidden meshes operation failed: ", result[1])
            else:
                print("Find hidden meshes successful. Log: ", result[1])
                # --- Execute Step 3: Decimate Meshes by Error ---
                carb.log_info("Running Step 3: Decimate Meshes...")
                result = optimizer_interface.execute_operation("decimateMeshes", execution_context, json.dumps(decimation_params))
                
                if not result[0]:
                    carb.log_error(f"Decimate meshes operation failed: {result[1]}")
                else:
                    carb.log_info(f"Decimate meshes successful. Log: {result[1]}")

print("--- Script finished. ---")

[INFO] merge: Created 7 Merged Meshes

[INFO] findHiddenMeshes: Found 17 hidden meshes

[INFO] decimateMeshes:
VertexCount: 309164 -> 54374 (82.412567)
FaceCount: 253304 -> 106740 (57.860912)

import omni.usd
from pxr import Sdf, Usd, UsdGeom, UsdShade
import carb

#The full path to the parent prim
TARGET_PRIM_PATH = "/tn__Release20211Carterv20ASM_WPDKOkCO/tn__BodyBoxASM1_lB8CzCl0/tn__BodyBoxEnclosure_qG8"

#The full path to the material prim
MATERIAL_PRIM_PATH = "/tn__Release20211Carterv20ASM_WPDKOkCO/Looks/Aluminum_Brushed_Light_Brushing" 

def apply_material_to_prim_and_children(target_path: str, material_path: str):
    """Finds a prim and applies a material to all geometry descendants."""
    
    stage = omni.usd.get_context().get_stage()
    parent_prim = stage.GetPrimAtPath(target_path)
    material_prim = stage.GetPrimAtPath(material_path)
    material_to_bind = UsdShade.Material(material_prim)

    # --- Iterate and Bind ---
    bound_count = 0
    for prim in Usd.PrimRange(parent_prim):
        if prim.IsA(UsdGeom.Mesh):
            # Bind the specific material object, not the generic prim.
            UsdShade.MaterialBindingAPI.Apply(prim).Bind(material_to_bind)
            carb.log_info(f"Successfully bound material to: {prim.GetPath()}")
            bound_count += 1
    if bound_count > 0:
        carb.log_info(f"--- Process Complete. Applied material to {bound_count} geometry prim(s). ---")
    else:
        carb.log_warning(f"--- Script Finished, but no geometry (Gprims) were found under '{target_path}'. ---")
# --- Run the main function with your configuration ---
if __name__ == "__main__":
    apply_material_to_prim_and_children(
        target_path=TARGET_PRIM_PATH, 
        material_path=MATERIAL_PRIM_PATH
    )

from pxr import Usd, Sdf

# 1. Define the path to your heavy geometry layer.
geometry_layer_path = './NovaCarter.usd'

# 2. Define the name for the new, slim interface layer we are creating.
# Note: make sure to adjust filepaths if you run this yourself
interface_layer_path = 'C:/Users/juslin/Downloads/nova.usd'

# Create a new, empty USD stage for our interface layer
stage = Usd.Stage.CreateNew(interface_layer_path)

# Define the main prim that will act as the "handle" for our robot
robot_prim_path = '/nova_carter'
robot_prim = stage.DefinePrim(robot_prim_path)

# Get the 'payloads' API on the prim
payloads_api = robot_prim.GetPayloads()

# Add the payload reference. This points to the geometry layer but does not
# load it immediately.
payloads_api.AddPayload(assetPath=geometry_layer_path)
print(f"Created interface layer and set payload to '{geometry_layer_path}'.")

# (Optional) Set the default variant to use when the payload is loaded.
variant_set = robot_prim.GetVariantSets().AddVariantSet('fidelity')
variant_set.SetVariantSelection('lightweight')
print("Set default variant to 'lightweight'.")

# Save the new interface layer. It will be a very small text file.
stage.GetRootLayer().Save()
print(f"Slim asset interface layer '{interface_layer_path}' created successfully.")