[Brace3D II] A flexible brace object for 3D. #manim #3D #brace

20241229_brace3d.py

from manim import *

class Brace3D(Brace):
    def __init__(self, line, rotation=0, **kwargs):
        flatline = Line(ORIGIN, line.get_length()*RIGHT)
        super().__init__(flatline, direction=np.array([0., -1., 0.]), **kwargs)
        dline = line.get_end()-line.get_start()
        self.rotate(angle=rotation, about_point=flatline.get_start(),axis=RIGHT)
        self.rotate(-np.asin(dline[2]/np.linalg.norm(dline)), about_point=flatline.get_start(), axis=UP)
        self.rotate(np.atan2(dline[1],dline[0]), about_point=flatline.get_start(), axis=OUT)
        self.shift(line.get_start()-flatline.get_start())

class brace3dtest(ThreeDScene):
    def construct(self):
        ax = ThreeDAxes(
                x_range=[0,20,5],
                y_range=[0,20,5],
                z_range=[0,20,5],
                x_length=5,
                y_length=5,
                z_length=5,
        ).add_coordinates()
        ax.shift(-ax.c2p(5,5,5))
        self.set_camera_orientation(focal_distance=1000)
        self.set_camera_orientation(phi=70 * DEGREES, theta=-70 * DEGREES)
        self.add(ax)
        dot = Dot3D(ax.c2p(15,10,10))
        self.add(dot)
        newline = Line(ax.c2p(0,0,0), dot.get_center())
        self.add(newline)
        ang = ValueTracker(0)
        brace = always_redraw(lambda:
            Brace3D(newline,rotation=ang.get_value(),buff=0.2)
        )
        self.add(brace)
        self.wait()
        self.play(ang.animate.set_value(2*PI),rate_func=rate_functions.linear,run_time=3)
        self.wait()