Add jaxsim.mujoco package with resources to render a scene using the Mujoco viewer

environment.yml

@@ -12,13 +12,18 @@ dependencies:
   - pptree
   - rod
   # Optional dependencies from setup.cfg
+  # [style]
   - black
   - isort
+  # [testing]
   - idyntree
   - pytest
   - pytest-forked
   - pytest-icdiff
   - robot_descriptions
+  # [viz]
+  - mediapy
+  - mujoco >= 3.0.0
   # System dependencies to run the tests
   - gz-sim7
   # Other packages

setup.cfg

@@ -73,6 +73,10 @@ testing =
     pytest-forked
     pytest-icdiff
     robot-descriptions
+viz =
+    mediapy
+    mujoco >= 3.0.0
 all =
     %(style)s
     %(testing)s
+    %(viz)s

src/jaxsim/mujoco/__init__.py

@@ -0,0 +1,3 @@
+from .loaders import RodModelToMjcf, SdfToMjcf, UrdfToMjcf
+from .model import MujocoModelHelper
+from .visualizer import MujocoVisualizer

src/jaxsim/mujoco/__main__.py

@@ -0,0 +1,192 @@
+import argparse
+import pathlib
+import sys
+import time
+
+import numpy as np
+
+from . import MujocoModelHelper, MujocoVisualizer, SdfToMjcf, UrdfToMjcf
+
+if __name__ == "__main__":
+
+    parser = argparse.ArgumentParser(
+        prog="jaxsim.mujoco",
+        description="Process URDF and SDF files for Mujoco usage.",
+    )
+
+    parser.add_argument(
+        "-d",
+        "--description",
+        required=True,
+        metavar="INPUT_FILE",
+        type=pathlib.Path,
+        help="Path to the URDF or SDF file.",
+    )
+
+    parser.add_argument(
+        "-m",
+        "--model-name",
+        metavar="NAME",
+        type=str,
+        default=None,
+        help="The target model of a SDF description if multiple models exists.",
+    )
+
+    parser.add_argument(
+        "-e",
+        "--export",
+        metavar="MJCF_FILE",
+        type=pathlib.Path,
+        default=None,
+        help="Path to the exported MJCF file.",
+    )
+
+    parser.add_argument(
+        "-f",
+        "--force",
+        action="store_true",
+        default=False,
+        help="Override the output MJCF file if it already exists (default: %(default)s).",
+    )
+
+    parser.add_argument(
+        "-p",
+        "--print",
+        action="store_true",
+        default=False,
+        help="Print in the stdout the exported MJCF string (default: %(default)s).",
+    )
+
+    parser.add_argument(
+        "-v",
+        "--visualize",
+        action="store_true",
+        default=False,
+        help="Visualize the description in the Mujoco viewer (default: %(default)s).",
+    )
+
+    parser.add_argument(
+        "-b",
+        "--base-position",
+        metavar=("x", "y", "z"),
+        nargs=3,
+        type=float,
+        default=None,
+        help="Override the base position (supports only floating-base models).",
+    )
+
+    parser.add_argument(
+        "-q",
+        "--base-quaternion",
+        metavar=("w", "x", "y", "z"),
+        nargs=4,
+        type=float,
+        default=None,
+        help="Override the base quaternion (supports only floating-base models).",
+    )
+
+    args = parser.parse_args()
+
+    # ==================
+    # Validate arguments
+    # ==================
+
+    # Expand the path of the URDF/SDF file if not absolute.
+    if args.description is not None:
+        args.description = (
+            (
+                args.description
+                if args.description.is_absolute()
+                else pathlib.Path.cwd() / args.description
+            )
+            .expanduser()
+            .absolute()
+        )
+
+        if not pathlib.Path(args.description).is_file():
+            msg = f"The URDF/SDF file '{args.description}' does not exist."
+            parser.error(msg)
+            sys.exit(1)
+
+    # Expand the path of the output MJCF file if not absolute.
+    if args.export is not None:
+        args.export = (
+            (
+                args.export
+                if args.export.is_absolute()
+                else pathlib.Path.cwd() / args.export
+            )
+            .expanduser()
+            .absolute()
+        )
+
+        if pathlib.Path(args.export).is_file() and not args.force:
+            msg = "The output file '{}' already exists, use '--force' to override."
+            parser.error(msg.format(args.export))
+            sys.exit(1)
+
+    # ================================================
+    # Load the URDF/SDF file and produce a MJCF string
+    # ================================================
+
+    match args.description.suffix.lower()[1:]:
+
+        case "urdf":
+            mjcf_string, assets = UrdfToMjcf().convert(urdf=args.description)
+
+        case "sdf":
+            mjcf_string, assets = SdfToMjcf().convert(
+                sdf=args.description, model_name=args.model_name
+            )
+
+        case _:
+            msg = f"The file extension '{args.description.suffix}' is not supported."
+            parser.error(msg)
+            sys.exit(1)
+
+    if args.print:
+        print(mjcf_string, flush=True)
+
+    # ========================================
+    # Write the MJCF string to the output file
+    # ========================================
+
+    if args.export is not None:
+        with open(args.export, "w+", encoding="utf-8") as file:
+            file.write(mjcf_string)
+
+    # =======================================
+    # Visualize the MJCF in the Mujoco viewer
+    # =======================================
+
+    if args.visualize:
+
+        mj_model_helper = MujocoModelHelper.build_from_xml(
+            mjcf_description=mjcf_string, assets=assets
+        )
+
+        viz = MujocoVisualizer(model=mj_model_helper.model, data=mj_model_helper.data)
+
+        with viz.open() as viewer:
+
+            with viewer.lock():
+                if args.base_position is not None:
+                    mj_model_helper.set_base_position(
+                        position=np.array(args.base_position)
+                    )
+
+                if args.base_quaternion is not None:
+                    mj_model_helper.set_base_orientation(
+                        orientation=np.array(args.base_quaternion)
+                    )
+
+            viz.sync(viewer=viewer)
+
+            while viewer.is_running():
+                time.sleep(0.500)
+
+    # =============================
+    # Exit the program with success
+    # =============================
+
+    sys.exit(0)