Allow for setting a default frame orientation

manimlib/camera/camera_frame.py

@@ -29,6 +29,7 @@ class CameraFrame(Mobject):
         self.center_point = center_point
         self.focal_dist_to_height = focal_dist_to_height
         self.view_matrix = np.identity(4)
+        self.default_orientation = Rotation.identity()
         super().__init__(**kwargs)
 
     def init_uniforms(self) -> None:
@@ -50,11 +51,15 @@ class CameraFrame(Mobject):
     def get_orientation(self):
         return Rotation.from_quat(self.uniforms["orientation"])
 
+    def make_orientation_default(self):
+        self.default_orientation = self.get_orientation()
+        return self
+
     def to_default_state(self):
         self.center()
         self.set_height(FRAME_HEIGHT)
         self.set_width(FRAME_WIDTH)
-        self.set_orientation(Rotation.identity())
+        self.set_orientation(self.default_orientation)
         return self
 
     def get_euler_angles(self):
@@ -101,7 +106,11 @@ class CameraFrame(Mobject):
         for i, var in enumerate([theta, phi, gamma]):
             if var is not None:
                 eulers[i] = var * units
-        self.set_orientation(Rotation.from_euler("zxz", eulers[::-1]))
+        if all(eulers == 0):
+            rot = Rotation.identity()
+        else:
+            rot = Rotation.from_euler("zxz", eulers[::-1])
+        self.set_orientation(rot)
         return self
 
     def reorient(

manimlib/scene/scene.py

@@ -18,6 +18,7 @@ from tqdm.auto import tqdm as ProgressDisplay
 from manimlib.animation.animation import prepare_animation
 from manimlib.animation.fading import VFadeInThenOut
 from manimlib.camera.camera import Camera
+from manimlib.camera.camera_frame import CameraFrame
 from manimlib.config import get_module
 from manimlib.constants import ARROW_SYMBOLS
 from manimlib.constants import DEFAULT_WAIT_TIME
@@ -63,6 +64,8 @@ class Scene(object):
     default_window_config: dict = dict()
     default_file_writer_config: dict = dict()
     samples = 0
+    # Euler angles, in degrees
+    default_frame_orientation = (0, 0)
 
     def __init__(
         self,
@@ -108,6 +111,10 @@ class Scene(object):
 
         # Core state of the scene
         self.camera: Camera = Camera(**self.camera_config)
+        self.frame: CameraFrame = self.camera.frame
+        self.frame.reorient(*self.default_frame_orientation)
+        self.frame.make_orientation_default()
+
         self.file_writer = SceneFileWriter(self, **self.file_writer_config)
         self.mobjects: list[Mobject] = [self.camera.frame]
         self.id_to_mobject_map: dict[int, Mobject] = dict()
@@ -971,3 +978,8 @@ class SceneState():
 
 class EndScene(Exception):
     pass
+
+
+class ThreeDScene(Scene):
+    samples = 4
+    default_frame_orientation = (-30, 70)