Manim cannot render imported Scenes

[rvodden]

Description of bug / unexpected behavior

Manim should be able to render scenes imported from other modules. As it stands, they cannot be found

Expected behavior

Manim can render scenes imported from other modules.

How to reproduce the issue

Code for reproducing the problem

I have created three files:

main.py:

from src import SceneOne
from manim import *

class SceneTwo(Scene):
    ...

src/__init__.py:

from .scene import SceneOne

src/scene.py:

from manim import * 

class SceneOne(Scene) :
    ...

when I run manim -ql main.py SceneTwo I get the expected output:

Manim Community v0.19.0

[10/31/25 09:05:21] INFO                                                                                                                                                                                                                               scene_file_writer.py:886
                             File ready at '/home/rvodden/Source/GarbageCollection/Series/bug_repro/media/images/main/SceneTwo_ManimCE_v0.19.0.png'                                                                                                                            
                                                                                                                                                                                                                                                                               
                    INFO     Rendered SceneTwo                                                                                                                                                                                                                     scene.py:255
                             Played 0 animations      

However when I run manim -ql main.py SceneOne, it cannot be rendered:

Manim Community v0.19.0

[10/31/25 08:57:09] ERROR                                                                                                                                                                                                                                     module_ops.py:106
                                SceneOne is not in the script                                                                                                                                                                                                                  
                                                                                                                                                                                                                                                                               
                    INFO                                                                                                                                                                                                                               scene_file_writer.py:886
                             File ready at '/home/rvodden/Source/GarbageCollection/Series/bug_repro/media/images/main/SceneTwo_ManimCE_v0.19.0.png'                                                                                                                            
                                                                                                                                                                                                                                                                               
                    INFO     Rendered SceneTwo                                                                                                                                                                                                                     scene.py:255
                             Played 0 animations  

</details>

System specifications

System Details

• OS (with version, e.g., Windows 10 v2004 or macOS 10.15 (Catalina)): Windows 11 WSL2 (running Ubuntu 24.04)
• RAM: 64GB
• Python version (python/py/python3 --version): 3.13.8
• Installed modules (provide output from pip list):

Package           Version
----------------- -----------
audioop-lts       0.2.2
av                13.1.0
beautifulsoup4    4.14.2
click             8.3.0
cloup             3.0.8
decorator         5.2.1
glcontext         3.0.0
isosurfaces       0.1.2
manim             0.19.0
ManimPango        0.6.1
mapbox_earcut     1.0.3
markdown-it-py    4.0.0
mdurl             0.1.2
moderngl          5.12.0
moderngl-window   3.1.1
networkx          3.5
numpy             2.3.4
pillow            12.0.0
pip               25.2
pycairo           1.28.0
pydub             0.25.1
pyglet            2.1.9
pyglm             2.8.2
Pygments          2.19.2
rich              14.2.0
scipy             1.16.3
screeninfo        0.8.1
skia-pathops      0.8.0.post2
soupsieve         2.8
srt               3.5.3
svgelements       1.9.6
tqdm              4.67.1
typing_extensions 4.15.0
watchdog          6.0.0

Additional comments

[rvodden]

This appears to be caused by some (IMHO) slightly overzealous code here: https://github.com/ManimCommunity/manim/blob/v0.19.0/manim/utils/module_ops.py#L81-L82

I believe that this is intended to remove the built in Scene types from the returned list. Alternative logic to filter out the builtin scenes, but include those imported by the user might be:

def get_scene_classes_from_module(module: types.ModuleType) -> list[type[Scene]]:
    from ..scene.scene import Scene

    def is_child_scene(obj: Any, module: types.ModuleType) -> bool:
        return (
            inspect.isclass(obj)
            and issubclass(obj, Scene)
            and obj != Scene
            and not obj.__module__.startswith("manim")
        )

    return [
        member[1]
        for member in inspect.getmembers(module, lambda x: is_child_scene(x, module))
    ]

I'm happy to submit a PR, but I'm also aware that this might be considered a breaking change. If it is considered a breaking change, then a command line option such as --include-imported-scenes could easily be added (and defaulted to off - persisting current behaviour).

[henrikmidtiby]

If you modify the main.py file to the following, you can effectively render SceneOne.

from src import SceneOne
from manim import *

class SceneTwo(Scene):
    ...

class SceneThree(SceneOne):
    ...

The idea is to create a new class SceneThree which inherit from SceneOne.

[henrikmidtiby]

A similar issue was reported here: #4264