使用python绘制3D图，并保存没有背景的png格式

import numpy as np
import matplotlib.pyplot as plt
fig = plt.figure(figsize=(9,9))
ax = fig.gca(projection='3d')
X = np.arange(-5, 5, 0.1)
Y = np.arange(-5, 5, 0.1)
X, Y = np.meshgrid(X, Y)
R = np.sqrt(X ** 2 + Y ** 2)
Z = np.sin(R)
surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=plt.cm.winter)
ax.grid(False)#默认True，风格线。
ax.set_xticks([])#不显示x坐标轴
ax.set_yticks([])#不显示y坐标轴
ax.set_zticks([])#不显示z坐标轴
plt.axis('off')#关闭所有坐标轴
plt.subplots_adjust(0, 0, 1, 1)
plt.savefig(f'没有背景.png', transparent=True, bbox_inches='tight', pad_inches=0.0)

使用plt.savefig()保存图像，其中参数transparent=True，这个设置会让坐标轴，以及图像补丁（也就是alpha为0的位置）都变为透明；bbox_inches和pad_inches的设置是为了保存图像时删除图像的白边。

效果如下：

简单曲面：

import numpy as np
import matplotlib.pyplot as plt
fig = plt.figure(figsize=(9,9))
ax = fig.gca(projection='3d')

x1 = np.arange(0, 5, 0.1)
x2 = np.arange(5, -0.1, -0.1)
X = np.append(x1,x2)


y1 = np.arange(0, 5, 0.1)
y2 = np.arange(5, -0.1, -0.1)
Y = np.append(y1,y2)

X, Y = np.meshgrid(X, Y)

R = X ** 2 + Y ** 2
Z = R
surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=plt.cm.winter)
ax.grid(False)#默认True，风格线。
ax.set_xticks([])#不显示x坐标轴
ax.set_yticks([])#不显示y坐标轴
ax.set_zticks([])#不显示z坐标轴
plt.axis('off')#关闭所有坐标轴
plt.subplots_adjust(0, 0, 1, 1)
plt.savefig(f'没有背景的.png', transparent=True, bbox_inches='tight', pad_inches=0.0)

凸面：

import numpy as np
import matplotlib.pyplot as plt
fig = plt.figure(figsize=(9,9))
ax = fig.gca(projection='3d')
X = np.arange(-5, 5, 0.1)
Y = np.arange(-5, 5, 0.1)
X, Y = np.meshgrid(X, Y)
# R = np.sqrt(X ** 2 + Y ** 2)
# Z = np.sin(R)

R = X ** 2 + Y ** 2
Z = 50 - R  # 让z等于R就是凹面
surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=plt.cm.winter)
ax.grid(False)#默认True，风格线。
ax.set_xticks([])#不显示x坐标轴
ax.set_yticks([])#不显示y坐标轴
ax.set_zticks([])#不显示z坐标轴
plt.axis('off')#关闭所有坐标轴
plt.subplots_adjust(0, 0, 1, 1)
plt.savefig(f'没有背景的.png', transparent=True, bbox_inches='tight', pad_inches=0.0)

默认凹面画法：

import numpy as np
import matplotlib.pyplot as plt
fig = plt.figure(figsize=(9,9))
ax = fig.gca(projection='3d')

x1 = np.arange(0, 5, 0.1)
x2 = np.arange(5, -0.1, -0.1)
X = np.append(x1,x2)


y1 = np.arange(0, 5, 0.1)
y2 = np.arange(5, -0.1, -0.1)
Y = np.append(y1,y2)

X, Y = np.meshgrid(X, Y)

R = X ** 2 + Y ** 2
Z = R
surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=plt.cm.winter)
ax.grid(False)#默认True，风格线。
ax.set_xticks([])#不显示x坐标轴
ax.set_yticks([])#不显示y坐标轴
ax.set_zticks([])#不显示z坐标轴
# plt.axis('off')#关闭所有坐标轴
plt.subplots_adjust(0, 0, 1, 1)
plt.savefig(f'没有背景的.png', transparent=True, bbox_inches='tight', pad_inches=0.0)