Suggestion / Issue with add_fixed_orientation_mobjects() in Manim OpenGL

[afeef08133-sys]

Hi everyone,

I've encountered a frustrating issue with add_fixed_orientation_mobjects() when working with text (or any mobject) in 3D scenes using Manim's OpenGL renderer.

What happens:

If you call add_fixed_orientation_mobjects() before you create or write the text (e.g., before Write() or Create() animation), the text appears instantly fully oriented but without any animation. Essentially, the object is added and visible before the animation plays, so the animation looks like it just draws on top of something already there.

If you call add_fixed_orientation_mobjects() after you write or create the text, the text first appears unoriented and then suddenly rotates to face the camera. This makes the animation jarring and visually distracting.

This behavior makes it very difficult to have nicely animated text or labels that always face the camera smoothly in 3D OpenGL scenes.

Why this matters:

In 3D visualizations, having labels or annotations that always face the camera (fixed orientation in 3D space) is crucial for readability. The Cairo backend supports this well, but OpenGL — which is the future of Manim with better performance and visuals — currently lacks proper support.

Possible impact:

Animations lose polish and look awkward with label flickering or unexpected appearance.

Users are forced to either avoid add_fixed_orientation_mobjects() or accept these visual glitches.

Suggestion:

I propose the Manim devs consider fixing or improving add_fixed_orientation_mobjects() behavior for OpenGL:

Ideally, the method should not add the mobject visibly before the animation, allowing the animation (Write/Create/FadeIn) to be the moment it appears.

When called after creation, the mobject should appear already fixed and oriented, without sudden rotation during the animation.

This small change would significantly improve the quality of 3D annotated scenes in Manim.

Thanks for considering!