Vectors

[subornoG]

Hi all! I've been trying to add two vectors, and show the resultant AND the original vectors as well, but have been unsuccessful so far. Could you please help me out. Thanks.

[behackl]

Hey! I'm not quite sure what you are asking for; what did you try already?

Should your animation look something like this?

Vectors.mp4

from manim import *

class Vectors(Scene):
    def construct(self):
        v1 = Vector(2*RIGHT)
        v2 = Vector(UP)
        v3 = Vector(v1.get_vector() + v2.get_vector())

        self.play(GrowArrow(v1), GrowArrow(v2))
        self.play(v2.animate.shift(v1.get_vector()))
        self.play(GrowArrow(v3))
        self.wait()

[subornoG]

Testing.mp4

Thanks, but I want to make a more general case of vector sum. I have done this, but when I set one vector rotating, the resultant doesn't follow. Also, why does the rotating vector seem to be warped?

from manim import *
#import numpy as np

class Testing(Scene):
    def construct(self):
        #pt = np.array((3,4))
        v = Vector(UP)
        v1 = Vector(LEFT)
        res = Vector(v.get_vector() + v1.get_vector())  
        animation = Rotate(v, angle = -2*PI, about_point = v.get_start(), run_time = 4)
        self.add(NumberPlane())
        self.play(Create(v), Create(v1))
        self.play(Create(res))
        self.play(animation)
        self.wait(1)

[kilacoda-old]

You might want to look into updaters:

from manim import *


class Testing(Scene):
    def construct(self):
        # pt = np.array((3,4))
        v = Vector(UP)
        v1 = Vector(LEFT)

        res = Vector(v.get_vector() + v1.get_vector())
        res.tip.scale(0.75)

        res.add_updater(
            lambda m: m.put_start_and_end_on(ORIGIN, v.get_vector() + v1.get_vector())
        )

        animation = Rotate(v, angle=-2 * PI, about_point=v.get_start(), run_time=4)

        self.add(NumberPlane())
        self.play(Create(v), Create(v1))
        self.play(Create(res))
        self.play(animation)
        self.wait(1)

Testing.mp4