manim

The error occurs because trimesh and pywavefront were present in requirements.txt but missing from install_requires in setup.cfg, so an editable install did not install them.

Immediate workaround:

# Activate your virtual environment first
source venv/bin/activate        # macOS/Linux
venv\Scripts\activate.bat       # Windows Command Prompt
.\venv\Scripts\Activate.ps1     # Windows PowerShell

# Install the missing dependencies
pip install trimesh pywavefront

Permanent fix: add both packages to install_requires in setup.cfg, then reinstall:

pip install -e .

The packaging issue was fixed in commit 4cec571c0; updating to a version containing that commit also resolves it.

In Manim v1.7.2, SVGMobject defaults stroke_width to 0.0, which overrides the stroke widths defined inside the SVG. As a workaround, pass stroke_width=None so the SVG's own stroke widths are preserved:

p = SVGMobject("Simple.svg", stroke_width=None)

The permanent fix is to upgrade to a Manim version containing the PR "Honor stroke widths declared in SVG files," which changes the default behavior so parsed per-path stroke widths are not reset to 0.0.

Replace pkg_resources with the modern importlib.metadata API in the package's __init__.py:

try:
    from importlib.metadata import version, PackageNotFoundError
except ImportError:  # Python < 3.8
    from importlib_metadata import version, PackageNotFoundError  # type: ignore

try:
    __version__ = version("manimgl")
except PackageNotFoundError:
    __version__ = "unknown"

Remove the old code:

import pkg_resources
__version__ = pkg_resources.get_distribution("manimgl").version

For Python versions earlier than 3.8, install the backport with pip install importlib-metadata. This eliminates the deprecation warning on Python 3.13 and later.

This happens because VectorField passes all sample points to your function as a batched (N, 2) array, while rotate_vector tries to multiply it by a 3×3 rotation matrix. Update Manim to the latest master containing the batched 2D rotation fix:

pip install -U git+https://github.com/3b1b/manim.git

If you installed from a local clone:

git pull
pip install -e .

As an immediate workaround, apply a 2D rotation directly instead of calling rotate_vector:

def rotate_2d(vector, angle):
    c, s = np.cos(angle), np.sin(angle)
    rotation = np.array([
        [c, -s],
        [s,  c],
    ])
    return np.asarray(vector) @ rotation.T

def curl_func(p):
    return rotate_2d(p / 3, PI / 2)

field_curl = VectorField(curl_func, axes)

This works for both single vectors and batched arrays of shape (N, 2).

The installation fails because ipython>=8.18.0 requires Python 3.9 or newer. Create the Conda environment with a supported Python version; use Python 3.10 because manimlib may also fail to import on Python 3.9:

conda create -n manim python=3.10
conda activate manim
pip install -e .

If the old environment already exists, remove it first with conda env remove -n manim, then recreate it.