manim/docs/source/installation/troubleshooting.rst

Troubleshooting
===============

Version incompatibility
***********************

Confusion and conflict between versions are by far the most common reasons
for installation failures. Some errors resulting from this are:

- ``There are no scenes in that module``
- ``ModuleNotFoundError: No module named 'manim'``
- ``ModuleNotFoundError: No module named 'manimlib'``

Some reasons that conflict may occur are:

- You followed any tutorial created before October 2020 (because the community edition did not exist before then)
- You cloned a repository on GitHub (installation of the community version for normal use does not require the cloning of any repository)
- Different import statements (explained below)
- You used documentation for multiple versions (such as the readme for 3b1b/manim and this documentation)

.. note::
   As this is the documentation for the community version, we can
   only help with the installation of this library. If you would like to
   install other versions of manim, please refer to their documentation.

Identifying files written for a different version of manim
----------------------------------------------------------

There are some distinctive features of different versions of manim that
can help in identifying what version of manim files are written for:

+--------------+-------------------------+----------------------------+-----------------------------------------+
| Feature      | ManimCE (this version)  | ManimGL                    | ManimCairo                              |
+==============+=========================+============================+=========================================+
| Import       | ``from manim import *`` | ``from manimlib import *`` | ``from manimlib.imports import *``      |
| statement    |                         |                            |                                         |
+--------------+-------------------------+----------------------------+-----------------------------------------+

If you are a beginner, you should only attempt to run files written for
your version. Files written for a different version of manim will
generally not work without some modification.

Identifying the version you are running
---------------------------------------

The community edition of manim should always state `Manim Community <version_number>`
as its first line of any command you run.

Identifying and removing conflicting versions of manim
------------------------------------------------------

Within the system or environment you are using to run manim, run the
following command in the terminal:

.. code-block:: bash

   pip list

The correct package for the community edition is simply ``manim``. If
you do not see this package listed, please refer back to our
installation guide to install it. If you see ``manimlib`` or ``manimce``
(actually an old version of the community edition), you should remove
them with:

.. code-block:: bash

   pip uninstall <package>


If you cloned manim from GitHub, you should either remove it
or run manim outside that folder.

Other errors
************

``pip install manim`` fails when installing manimpango?
-------------------------------------------------------
This most likely means that pip was not able to use our pre-built wheels
of ``manimpango``. Let us know (via our `Discord <https://www.manim.community/discord/>`_
or by opening a
`new issue on GitHub <https://github.com/ManimCommunity/ManimPango/issues/new>`_)
which architecture you would like to see supported, and we'll see what we
can do about it.

To fix errors when installing ``manimpango``, you need to make sure you
have all the necessary build requirements. Check out the detailed
instructions given in
`the BUILDING section <https://github.com/ManimCommunity/ManimPango#BUILDING>`_
of the corresponding `GitHub repository <https://github.com/ManimCommunity/ManimPango>`_.


(Windows) OSError: dlopen() failed to load a library: pango
-----------------------------------------------------------

This should be fixed in Manim's latest version, update
using ``pip install --upgrade manim``.



Some letters are missing from Text/Tex output
---------------------------------------------

If you have recently installed TeX you may need to build the fonts it
uses. This can be done by running:

.. code-block:: bash

  fmtutil -sys --all


.. _dvisvgm-troubleshoot:

Installation does not support converting PDF to SVG
---------------------------------------------------

First, make sure your ``dvisvgm`` version is at least 2.4:

.. code-block:: bash

  dvisvgm --version


If you do not know how to update ``dvisvgm``, please refer to your operating system's documentation.

Second, check whether your ``dvisvgm`` supports PostScript specials. This is
needed to convert from PDF to SVG.

.. code-block:: bash

  dvisvgm -l


If the output to this command does **not** contain ``ps  dvips PostScript specials``,
this is a bad sign. In this case, run

.. code-block:: bash

  dvisvgm -h


If the output does **not** contain ``--libgs=filename``, this means your
``dvisvgm`` does not currently support PostScript. You must get another binary.

If, however, ``--libgs=filename`` appears in the help, that means that your
``dvisvgm`` needs the Ghostscript library to support PostScript. Search for
``libgs.so`` (on Linux, probably in ``/usr/local/lib`` or ``/usr/lib``) or
``gsdll32.dll`` (on 32-bit Windows, probably in ``C:\windows\system32``) or
``gsdll64.dll`` (on 64-bit Windows, probably in ``c:\windows\system32`` -- yes
32) or ``libgsl.dylib`` (on Mac OS, probably in ``/usr/local/lib`` or
``/opt/local/lib``). Please look carefully, as the file might be located
elsewhere, e.g. in the directory where Ghostscript is installed.

When you have found the library, try (on Mac OS or Linux)

.. code-block:: bash

  export LIBGS=<path to your library including the file name>
  dvisvgm -l

or (on Windows)

.. code-block:: bat

  set LIBGS=<path to your library including the file name>
  dvisvgm -l


You should now see ``ps    dvips PostScript specials`` in the output. Refer to
your operating system's documentation to find out how you can set or export the
environment variable ``LIBGS`` automatically whenever you open a shell.

As a last check, you can run

.. code-block:: bash

  dvisvgm -V1

(while still having ``LIBGS`` set to the correct path, of course.) If ``dvisvgm``
can find your Ghostscript installation, it will be shown in the output together
with the version number.

If you do not have the necessary library on your system, please refer to your
operating system's documentation to find out where you can get it and how you
have to install it.

If you are unable to solve your problem, check out the `dvisvgm FAQ <https://dvisvgm.de/FAQ/>`_.

(Windows) ``Python is not recognized as an internal or external command, operable program or batch file.``
----------------------------------------------------------------------------------------------------------

To fix this, you need to add the Python executable to your ``PATH`` environment variable.
Follow the steps in `this StackExchange answer <https://superuser.com/questions/143119/how-do-i-add-python-to-the-windows-path/143121#143121>`__.

``choco install manimce`` failed
--------------------------------

If ``choco install manimce`` failed,
it is likely because Python was not added to your ``PATH`` variable properly.
Try running the following commands in your terminal:

1. ``py --version``
2. ``python --version``
3. ``py3 --version``
4. ``python3 --version``

Minimally, ``py --version`` and ``python --version`` should return a version.
If none of these commands are recognized,
this means that Python was installed on your system, but was not added to PATH.
See above for directions to add it to your PATH variable.

If any of these commands open the Windows store,
this is likely interfering with the process.
See below to fix aliases.

(Windows) Fix Aliases
---------------------

1. Go to the Windows Settings.
2. Under Apps and Features, there are application execution aliases.
3. Within this menu disable the alias(es) that are causing the issue (``python`` and/or ``python3``).

``IndexError: List index out of range``
---------------------------------------

Did you install LaTeX using MiKTeX? If so, open the MiKTeX console,
install the ``cm-super`` package, then delete the ``media`` directory and
try to render the scene again.

Config
------

We've dropped the use of CONFIG in the
Community Version :doc:`version 0.2.0<../changelog/0.2.0-changelog>`, released in January 2021.
This means parameters that were previously specified in the
CONFIG dictionary should now be passed directly into the constructor.
Practically, this means that old constructions like:

.. code-block:: python

  class SomeMobject(Thing):
      CONFIG = {
          "stroke_color": RED,
          "fill_opacity": 0.7,
          "radius": 3,
          "my_awesome_property": 42,
      }
      # add methods here

should now be defined like:

.. code-block:: python

  class SomeMobject(VMobject):
      def __init__(
          self,
          stroke_color=RED,
          fill_opacity=0.7,
          radius=3,
          my_awesome_property=42,
          **kwargs
      ):
          self.radius = 3
          self.my_awesome_property = 42
          super().__init__(
              stroke_color=stroke_color, fill_opacity=fill_opacity, **kwargs
          )  # passing arguments into the parent class
          # add methods here

For scenes, this is even easier:

.. code-block:: python

  class Test(Scene):
      CONFIG = {"a": 1, "b": 2}

becomes:

.. code-block:: python

  class Test(Scene):
      def construct(self):
          self.a = 1
          self.b = 2

A python command does not work
------------------------------

If a python command does not work,
try adding ``python -m``  in front of it.
For example, if ``pip install manim`` does not work, you can try ``python -m pip install manim``.

undefined symbol
----------------

If you are using anaconda, run the following command:

.. code-block:: bash

  conda install -c conda-forge pycairo