Refactor codebase to improve performance, maintainability and usability

[flferretti]

This PR enhances the codebase by fixing typos, refactoring classes, and optimizing Gazebo SDF processing with caching and batch support. Moreover, it updates the build system to use hatchling and improves the command-line interface.

First loading run:

# %timeit -n1 -r1 rod.Sdf.load(model_path)
< 678 ms ± 0 ns per loop (mean ± std. dev. of 1 run, 1 loop each)
> 592 ms ± 0 ns per loop (mean ± std. dev. of 1 run, 1 loop each)

Successive loading run:

# %timeit rod.Sdf.load(model_path)
< 657 ms ± 39.7 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)
> 12.1 ms ± 396 μs per loop (mean ± std. dev. of 7 runs, 100 loops each)

Switching model frame convention to URDF:

# %timeit sdf.model.switch_frame_convention(frame_convention=rod.FrameConvention.Urdf)
< 196 ms ± 4.98 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)
> 168 ms ± 9.18 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)

Exporting to URDF:

# %timeit UrdfExporter(pretty=True, gazebo_preserve_fixed_joints=True).to_urdf_string(sdf=sdf)
< 237 ms ± 2.44 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)
> 206 ms ± 9.41 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)

Test Script

import icub_models
import rod
from rod.urdf.exporter import UrdfExporter

model_path = icub_models.get_model_file("iCubGazeboV2_5")

# First loading run
%timeit -n1 -r1 _ = rod.Sdf.load(model_path)

# Successive loading run
%timeit _ = rod.Sdf.load(model_path)

sdf = rod.Sdf.load(model_path)

# Switching model frame convention to URDF
%timeit sdf.model.switch_frame_convention(frame_convention=rod.FrameConvention.Urdf)

# Exporting to URDF
%timeit _ = UrdfExporter(pretty=True, gazebo_preserve_fixed_joints=True).to_urdf_string(sdf=sdf)

[Copilot]

Pull request overview

This PR refactors key parts of ROD to improve performance and maintainability, notably optimizing Gazebo sdformat processing via caching and simplifying several internal transformation/export pipelines. It also modernizes packaging by switching to hatchling/hatch-vcs and improves the CLI’s UX and version reporting.

Changes:

• Added cached processing + batch helpers for Gazebo sdformat model description processing.
• Refactored frame convention switching and kinematics transform computation for simpler flow and caching.
• Modernized packaging/build (move to hatchling, add console script), and improved CLI/help text and version handling.

Reviewed changes

Copilot reviewed 12 out of 14 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/rod/utils/gazebo.py	Adds cached sdformat processing and a batch API; changes temp-file strategy for speed.
src/rod/utils/frame_convention.py	Refactors frame-convention switching into helper functions and uses updated TreeTransforms API.
src/rod/urdf/exporter.py	Restructures URDF export code into smaller helpers, adds type aliases, and updates logging usage.
src/rod/sdf/common.py	Moves imports to module scope for efficiency/clarity in pose transform computation.
src/rod/kinematics/tree_transforms.py	Reworks transform computation to cache paths and adds cache management helpers.
src/rod/kinematics/kinematic_tree.py	Refactors kinematic tree building into smaller helpers and changes indexing logic.
src/rod/main.py	Improves CLI help text, adds robust version lookup, and ensures consistent exit behavior.
src/rod/init.py	Exposes package version via rod._version when available.
setup.py	Removes legacy setuptools entrypoint.
pyproject.toml	Switches build backend to hatchling, adds console script entry, configures VCS version file.
pixi.lock	Updates dependency lockfile.
environment.yml	Adds dev/test and packaging tools; reorganizes dependency comments.
README.md	Fixes spelling (“definitely”).
.gitignore	Ignores hatch-generated _version.py and VS Code settings.

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