adds utility for urdf conversion

.gitignore

@@ -7,6 +7,12 @@
 **/*.dmp
 **/.thumbs
 
+# No USD files allowed in the repo
+**/*.usd
+**/*.usda
+**/*.usdc
+**/*.usdz
+
 # Python
 .DS_Store
 **/*.egg-info/

source/tools/check_instanceable.py

@@ -70,7 +70,7 @@
 from omni.isaac.core.utils.carb import set_carb_setting
 
 from omni.isaac.orbit.utils import Timer
-from omni.isaac.orbit.utils.nucleus import check_file_path
+from omni.isaac.orbit.utils.assets import check_file_path
 
 
 def main():

source/tools/convert_urdf.py

@@ -0,0 +1,181 @@
+# Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES, ETH Zurich, and University of Toronto
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+"""
+Utility to convert a URDF into USD format.
+
+Unified Robot Description Format (URDF) is an XML file format used in ROS to describe all elements of
+a robot. For more information, see: http://wiki.ros.org/urdf
+
+This script uses the URDF importer extension from Isaac Sim (``omni.isaac.urdf_importer``) to convert a
+URDF asset into USD format. It is designed as a convenience script for command-line use. For more
+information on the URDF importer, see the documentation for the extension:
+https://docs.omniverse.nvidia.com/app_isaacsim/app_isaacsim/ext_omni_isaac_urdf.html
+
+
+positional arguments:
+  input               The path to the input URDF file.
+  output              The path to store the USD file.
+
+optional arguments:
+  -h, --help          show this help message and exit
+  --headless          Force display off at all times. (default: False)
+  --merge_joints, -m  Consolidate links that are connected by fixed joints. (default: False)
+  --fix_base, -f      Fix the base to where it is imported. (default: False)
+  --gym, -g           Make the asset instanceable for efficient cloning. (default: False)
+
+"""
+
+"""Launch Isaac Sim Simulator first."""
+
+
+import argparse
+import contextlib
+
+# omni-isaac-orbit
+from omni.isaac.kit import SimulationApp
+
+# add argparse arguments
+parser = argparse.ArgumentParser("Utility to convert a URDF into USD format.")
+parser.add_argument("input", type=str, help="The path to the input URDF file.")
+parser.add_argument("output", type=str, help="The path to store the USD file.")
+parser.add_argument("--headless", action="store_true", default=False, help="Force display off at all times.")
+parser.add_argument(
+    "--merge_joints",
+    "-m",
+    action="store_true",
+    default=False,
+    help="Consolidate links that are connected by fixed joints.",
+)
+parser.add_argument(
+    "--fix_base", "-f", action="store_true", default=False, help="Fix the base to where it is imported."
+)
+parser.add_argument(
+    "--gym", "-g", action="store_true", default=False, help="Make the asset instanceable for efficient cloning."
+)
+args_cli = parser.parse_args()
+
+# launch omniverse app
+config = {"headless": args_cli.headless}
+simulation_app = SimulationApp(config)
+
+
+"""Rest everything follows."""
+
+import os
+
+import carb
+import omni.isaac.core.utils.stage as stage_utils
+import omni.kit.commands
+from omni.isaac.core.simulation_context import SimulationContext
+
+from omni.isaac.orbit.utils.assets import check_file_path
+
+_DRIVE_TYPE = {
+    "none": 0,
+    "position": 1,
+    "velocity": 2,
+}
+"""Mapping from drive name to URDF importer drive number."""
+
+_NORMALS_DIVISION = {
+    "catmullClark": 0,
+    "loop": 1,
+    "bilinear": 2,
+    "none": 3,
+}
+"""Mapping from normals division name to URDF importer normals division number."""
+
+
+def main():
+    # check valid file path
+    urdf_path = args_cli.input
+    if not os.path.isabs(urdf_path):
+        urdf_path = os.path.abspath(urdf_path)
+    if not check_file_path(urdf_path):
+        raise ValueError(f"Invalid file path: {urdf_path}")
+    # create destination path
+    dest_path = args_cli.output
+    if not os.path.isabs(dest_path):
+        dest_path = os.path.abspath(dest_path)
+    if os.path.exists(dest_path):
+        carb.log_warn(f"Destination file already exists: {dest_path}. Overwriting...")
+    if not os.path.exists(os.path.dirname(dest_path)):
+        os.makedirs(os.path.dirname(dest_path))
+
+    # Import URDF config
+    _, urdf_config = omni.kit.commands.execute("URDFCreateImportConfig")
+
+    # Set URDF config
+    # -- stage settings -- dont need to change these.
+    urdf_config.set_distance_scale(1.0)
+    urdf_config.set_up_vector(0, 0, 1)
+    urdf_config.set_create_physics_scene(False)
+    urdf_config.set_make_default_prim(True)
+    # -- instancing settings
+    urdf_config.set_make_instanceable(args_cli.gym)
+    urdf_config.set_instanceable_usd_path("Props/instanceable_meshes.usd")
+    # -- asset settings
+    urdf_config.set_density(0.0)
+    urdf_config.set_import_inertia_tensor(True)
+    urdf_config.set_convex_decomp(False)
+    urdf_config.set_subdivision_scheme(_NORMALS_DIVISION["bilinear"])
+    # -- physics settings
+    urdf_config.set_fix_base(args_cli.fix_base)
+    urdf_config.set_self_collision(False)
+    urdf_config.set_merge_fixed_joints(args_cli.merge_joints)
+    # -- drive settings
+    # note: we set these to none because we want to use the default drive settings.
+    urdf_config.set_default_drive_type(_DRIVE_TYPE["none"])
+    # urdf_config.set_default_drive_strength(1e7)
+    # urdf_config.set_default_position_drive_damping(1e5)
+
+    # Print info
+    print("-" * 80)
+    print("-" * 80)
+    print(f"Input URDF file: {urdf_path}")
+    print(f"Saving USD file: {dest_path}")
+    print("URDF importer config:")
+    for key in dir(urdf_config):
+        if not key.startswith("__"):
+            try:
+                # get attribute
+                attr = getattr(urdf_config, key)
+                # check if attribute is a function
+                if callable(attr):
+                    continue
+                # print attribute
+                print(f"\t{key}: {attr}")
+            except TypeError:
+                # this is only the case for subdivison scheme
+                pass
+    print("-" * 80)
+    print("-" * 80)
+
+    # Import URDF file
+    omni.kit.commands.execute(
+        "URDFParseAndImportFile", urdf_path=urdf_path, import_config=urdf_config, dest_path=dest_path
+    )
+
+    # Simulate scene (if not headless)
+    if not args_cli.headless:
+        # Open the stage with USD
+        stage_utils.open_stage(dest_path)
+        # Load kit helper
+        sim = SimulationContext(stage_units_in_meters=1.0)
+        # stage_utils.add_reference_to_stage(dest_path, "/Robot")
+        # Reinitialize the simulation
+        # Run simulation
+        with contextlib.suppress(KeyboardInterrupt):
+            while True:
+                # perform step
+                sim.step()
+
+
+if __name__ == "__main__":
+    # Run cloning example
+    main()
+    # Close the simulator
+    simulation_app.close()