使用 matplotlib 库绘制三维空间中的箭头时，出现以下问题：
- 箭头太短，导致箭头无法彼此相交，也无法触及虚线。
- 箭头末端不平滑，存在锯齿状边缘。
2、解决方案
为了解决上述问题，可以采用以下方法：
- 在创建箭头时，使用
shrinkA和shrinkB参数来调整箭头的长度。这两个参数控制箭头的起始端和末端收缩的比例。通过减小这两个参数的值，可以延长箭头，使其能够彼此相交并触及虚线。 - 使用
mutation_scale参数来调整箭头末端的平滑度。这个参数控制箭头的末端形状，值越大，箭头末端越平滑。通过增加mutation_scale的值，可以使箭头末端更加平滑。
以下代码实现了上述的解决方案：
import numpy as np
from matplotlib import pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
from matplotlib.patches import FancyArrowPatch
from mpl_toolkits.mplot3d import proj3d
class Arrow3D(FancyArrowPatch):
def __init__(self, xs, ys, zs, *args, **kwargs):
FancyArrowPatch.__init__(self, (0,0), (0,0), *args, **kwargs)
self._verts3d = xs, ys, zs
def draw(self, renderer):
xs3d, ys3d, zs3d = self._verts3d
xs, ys, zs = proj3d.proj_transform(xs3d, ys3d, zs3d, renderer.M)
self.set_positions((xs[0],ys[0]),(xs[1],ys[1]))
FancyArrowPatch.draw(self, renderer)
def Rx(phi):
return np.array([[1, 0, 0],
[0, np.cos(phi), -np.sin(phi)],
[0, np.sin(phi), np.cos(phi)]])
def Ry(theta):
return np.array([[np.cos(theta), 0, np.sin(theta)],
[0, 1, 0],
[-np.sin(theta), 0, np.cos(theta)]])
def Rz(psi):
return np.array([[np.cos(psi), -np.sin(psi), 0],
[np.sin(psi), np.cos(psi), 0],
[0, 0, 1]])
# define origin
o = np.array([0,0,0])
# define ox0y0z0 axes
x0 = np.array([1,0,0])
y0 = np.array([0,1,0])
z0 = np.array([0,0,1])
# define ox1y1z1 axes
psi = 20 * np.pi / 180
x1 = Rz(psi).dot(x0)
y1 = Rz(psi).dot(y0)
z1 = Rz(psi).dot(z0)
# define ox2y2z2 axes
theta = 10 * np.pi / 180
x2 = Rz(psi).dot(Ry(theta)).dot(x0)
y2 = Rz(psi).dot(Ry(theta)).dot(y0)
z2 = Rz(psi).dot(Ry(theta)).dot(z0)
# define ox3y3z3 axes
phi = 30 * np.pi / 180
x3 = Rz(psi).dot(Ry(theta)).dot(Rx(phi)).dot(x0)
y3 = Rz(psi).dot(Ry(theta)).dot(Rx(phi)).dot(y0)
z3 = Rz(psi).dot(Ry(theta)).dot(Rx(phi)).dot(z0)
# produce figure
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
arrow_prop_dict = dict(mutation_scale=20, arrowstyle='-|>', color='k', shrinkA=0, shrinkB=0)
# plot ox0y0z0 axes
a = Arrow3D([o[0], x0[0]], [o[1], x0[1]], [o[2], x0[2]], **arrow_prop_dict)
ax.add_artist(a)
a = Arrow3D([o[0], y0[0]], [o[1], y0[1]], [o[2], y0[2]], **arrow_prop_dict)
ax.add_artist(a)
a = Arrow3D([o[0], z0[0]], [o[1], z0[1]], [o[2], z0[2]], **arrow_prop_dict)
ax.add_artist(a)
# plot ox1y1z1 axes
a = Arrow3D([o[0], x1[0]], [o[1], x1[1]], [o[2], x1[2]], **arrow_prop_dict)
ax.add_artist(a)
a = Arrow3D([o[0], y1[0]], [o[1], y1[1]], [o[2], y1[2]], **arrow_prop_dict)
ax.add_artist(a)
a = Arrow3D([o[0], z1[0]], [o[1], z1[1]], [o[2], z1[2]], **arrow_prop_dict)
ax.add_artist(a)
# draw dotted arc in x0y0 plane
arc = np.arange(-5,116) * np.pi / 180
p = np.array([np.cos(arc),np.sin(arc),arc * 0])
ax.plot(p[0,:],p[1,:],p[2,:],'k--')
# mark z0 rotation angles (psi)
arc = np.linspace(0,psi)
p = np.array([np.cos(arc),np.sin(arc),arc * 0]) * 0.6
ax.plot(p[0,:],p[1,:],p[2,:],'k')
p = np.array([-np.sin(arc),np.cos(arc),arc * 0]) * 0.6
ax.plot(p[0,:],p[1,:],p[2,:],'k')
# plot ox2y2z2 axes
a = Arrow3D([o[0], x2[0]], [o[1], x2[1]], [o[2], x2[2]], **arrow_prop_dict)
ax.add_artist(a)
a = Arrow3D([o[0], y2[0]], [o[1], y2[1]], [o[2], y2[2]], **arrow_prop_dict)
ax.add_artist(a)
a = Arrow3D([o[0], z2[0]], [o[1], z2[1]], [o[2], z2[2]], **arrow_prop_dict)
ax.add_artist(a)
# draw dotted arc in x1z1 plane
arc = np.arange(-5,105) * np.pi / 180
p = np.array([np.sin(arc),arc * 0,np.cos(arc)])
p = Rz(psi).dot(p)
ax.plot(p[0,:],p[1,:],p[2,:],'k--')
# mark y1 rotation angles (theta)
arc = np.linspace(0,theta)
p = np.array([np.cos(arc),arc * 0,-np.sin(arc)]) * 0.6
p = Rz(psi).dot(p)
ax.plot(p[0,:],p[1,:],p[2,:],'k')
p = np.array([np.sin(arc),arc * 0,np.cos(arc)]) * 0.6
p = Rz(psi).dot(p)
ax.plot(p[0,:],p[1,:],p[2,:],'k')
# plot ox3y3z3 axes
a = Arrow3D([o[0], x3[0]], [o[1], x3[1]], [o[2], x3[2]], **arrow_prop_dict)
ax.add_artist(a)
a = Arrow3D([o[0], y3[0]], [o[1], y3[1]], [o[2], y3[2]], **arrow_prop_dict)
ax
