在VPython中如何创建两个向量之间的夹角？

Question

我正在尝试使用vpython创建两个向量之间的角度符号。这些向量是源向量和该向量的x-y投影。我正在使用vpython软件包，特别是从vpython的shapes模块中使用arc。

from vpython import *
import numpy as nump


scene2 = canvas(title='Source Vector',
     width=800, height=600,
     center=vector(0,0,0), background=color.white)

scene2.select()

geophone = pyramid(pos=vector(0,0,0), size=vector(2,2,2),
                  color = color.green, up = vector(-1,0,0))

shot_loc = sphere(pos=vector(-20,30,-20), 
                size=vector(2,2,2), color= color.red)

shot_loc_label = label(pos=shot_loc.pos,
    text='Vib Shot', xoffset=-30,
    yoffset=30, space=10,
    height=12, 
    font='serif')

ray_vector = arrow(pos=vector(0,0,0),  axis=shot_loc.pos,
                   shaftwidth=0.2, color= color.blue, length  =40, headlength = 2, headwidth =1)

ray_vec_label = label(pos=(ray_vector.axis - ray_vector.pos)/2,
    text='Ray Vector', xoffset=-30,
    yoffset=30, space=10,
    height=12, 
    font='sans')

source_vector = arrow(pos=vector(0,0,0),  axis= vector(20,-30, 20),
                   shaftwidth=0.2, color= color.red, length  =30, headlength = 2, headwidth =1)

projection_of_source_vector = cylinder(pos=vector(0,0,0),  axis= vector(20,0, 20),
                   radius=0.2, color=color.green)

source_vec_label = label(pos=source_vector.axis,
    text='Source Vector', xoffset=30,
    yoffset=30, space=10,
    height=12, 
    font='sans')





plunge_angle = diff_angle(vector(20,0, 20),vector(20,-30, 20))

plung_arc = shapes.circle(radius=10, angle1=0, angle2=plunge_angle, np=10, rotate=90)



extrusion(path=[vector(20,0, 20), vector(20,-30, 20)], 
          shape=plung_arc)


x_axis = arrow(pos=vector(-50,0,0),  axis=vector(50,0,0), shaftwidth=0.2,
               color= color.black, length  =100, headlength = 2, headwidth =1)

z_axis = arrow(pos=vector(0,-40,0),  axis=vector(0,40,0), shaftwidth=0.2,
               color= color.black, length  =80, headlength = 2, headwidth =1)

y_axis = arrow(pos=vector(0,0,40),  axis=vector(0,0,-40), shaftwidth=0.2,
               color= color.black, length  =80, headlength = 3, headwidth =2)



T_x = text(text='X',
     align='center', color=color.black, pos = vector(-52,0,0), 
           billboard =True, height =2)

T_y = text(text='Z',
     align='center', color=color.black, pos = vector(0,-43,0),
           billboard =True, height =2)

T_z = text(text='Y',
     align='center', color=color.black, pos = vector(0,0, 43),
           billboard =True, height =2)

T_x.width = 2*T_x.width
T_y.width = 2*T_y.width
T_z.width = 2*T_z.width

3D笛卡尔

- Khalil Al Hooti

---

我认为您需要更详细地描述您尝试实现的内容以及哪些方面出了问题。 - skrx

感谢您的评论。我想在vpython中创建两个向量之间的封闭弧，并使用角度符号进行标注。这两个向量如附图所示，即源向量及其在X-Y平面上的投影。目前无法正常创建弧线。@skrx - Khalil Al Hooti

Answer 1

终于自己搞定了。这段代码在jupyter notebook中编写，其结果如附图所示。我正在使用可以在jupyter notebook中运行的vpython新版本。

唯一无法完成的是使用Latex编写theta和alpha。

from vpython import *
import numpy as nump


scene2 = canvas(width=800, height=600,
     center=vector(0,0,0), background=color.white)

scene2.select()

geophone = pyramid(pos=vector(0,0,0), size=vector(2,2,2),
                  color = color.green, up = vector(-1,0,0))

geophone_label = label(pos=geophone.pos,
    text='Geophone', xoffset=-30,
    yoffset=-20, space=10,
    height=12, 
    font='sans')

shot_loc = sphere(pos=vector(-20,30,-20), 
                size=vector(2,2,2), color= color.red)

shot_loc_label = label(pos=shot_loc.pos,
    text='Vib Shot', xoffset=-30,
    yoffset=30, space=10,
    height=12, 
    font='sans')

ray_vector = arrow(pos=vector(0,0,0),  axis=shot_loc.pos,
                   shaftwidth=0.2, color= color.blue, length  =40, headlength = 2,
                   headwidth =1)

ray_vec_label = label(pos=(ray_vector.axis - ray_vector.pos)/2,
    text='Ray Vector', xoffset=-30,
    yoffset=30, space=10,
    height=12, 
    font='sans')

source_vector = arrow(pos=vector(0,0,0),  axis= vector(20,-30, 20),
                   shaftwidth=0.2, color= color.red, length  =30, headlength = 2,
                      headwidth =1)

projection_of_source_vector = cylinder(pos=vector(0,0,0),  axis= vector(20,0, 20),
                   radius=0.2, color=color.green)

source_vec_label = label(pos=source_vector.axis,
    text='Source Vector', xoffset=30,
    yoffset=30, space=10,
    height=12, 
    font='sans')




plunge_angle = diff_angle(vector(20,0, 20),vector(20,-30, 20))

plung_arc = shapes.arc(radius=10, angle1=0, angle2=-plunge_angle)

b = cross(vector(20,0, 20),vector(20,-30, 20))
norm_vector = norm(b)

extrusion(path=[vector(0,0, 0), norm_vector], 
          shape=plung_arc)

plunge_label = label(pos=vector(4,-4,4),
    text='α', xoffset=30,
    yoffset=-20, space=10,
    height=12, 
    font='sans')



back_azimuth_angle = diff_angle(vector(20,0, 20),vector(0,0, -1))
back_azimuth_arc = shapes.arc(radius=10, angle1=0, angle2=back_azimuth_angle)

c = cross(vector(20,0, 20),vector(0,0, -1))
norm_vector_azimth = norm(c)

extrusion(path=[vector(0,0, 0), norm_vector_azimth], 
          shape=back_azimuth_arc)

azimuth_label = label(pos=vector(3,0,-2),
    text='θ', xoffset=30,
    yoffset=30, space=10,
    height=12, 
    font='sans')


x_axis = arrow(pos=vector(-50,0,0),  axis=vector(50,0,0), shaftwidth=0.2,
               color= color.black, length  =100, headlength = 2, headwidth =1)

z_axis = arrow(pos=vector(0,-40,0),  axis=vector(0,40,0), shaftwidth=0.2,
               color= color.black, length  =80, headlength = 2, headwidth =1)

y_axis = arrow(pos=vector(0,0,40),  axis=vector(0,0,-40), shaftwidth=0.2,
               color= color.black, length  =80, headlength = 3, headwidth =1)



T_x = text(text='X',
     align='center', color=color.black, pos = vector(-52,0,0), 
           billboard =True, height =2)

T_y = text(text='Z',
     align='center', color=color.black, pos = vector(0,-43,0),
           billboard =True, height =2)

T_z = text(text='Y',
     align='center', color=color.black, pos = vector(0,0, 43),
           billboard =True, height =2)

T_x.width = 2*T_x.width
T_y.width = 2*T_y.width
T_z.width = 2*T_z.width

- Khalil Al Hooti