VTK Learning Thirty-one - pyvista

pyvista is  a high-level API to the VTK

创建规则网格曲面

# sphinx_gallery_thumbnail_number = 2
import pyvista as pv
import numpy as np

生成一个二维的正弦曲面

# Make data
x = np.arange(-10, 10, 0.25)
y = np.arange(-10, 10, 0.25)
x, y = np.meshgrid(x, y)
r = np.sqrt(x ** 2 + y ** 2)
z = np.sin(r)

# Create and plot structured grid
grid = pv.StructuredGrid(x, y, z)
grid.plot()

# Plot mean curvature as well 显示曲面的平均曲率
grid.plot_curvature(clim=[-1, 1])

访问网格曲面的点集

grid.points

pyvista_ndarray([[-10.        , -10.        ,   0.99998766],
                 [-10.        ,  -9.75      ,   0.98546793],
                 [-10.        ,  -9.5       ,   0.9413954 ],
                 ...,
                 [  9.75      ,   9.25      ,   0.76645876],
                 [  9.75      ,   9.5       ,   0.86571785],
                 [  9.75      ,   9.75      ,   0.93985707]])

生成点集(n*3)pv.PolyData.points

def make_point_set():
    """Ignore the contents of this function. Just know that it returns an
    n by 3 numpy array of structured coordinates."""
    n, m = 29, 32
    x = np.linspace(-200, 200, num=n) + np.random.uniform(-5, 5, size=n)
    y = np.linspace(-200, 200, num=m) + np.random.uniform(-5, 5, size=m)
    xx, yy = np.meshgrid(x, y)
    A, b = 100, 100
    zz = A * np.exp(-0.5 * ((xx / b) ** 2.0 + (yy / b) ** 2.0))
    points = np.c_[xx.reshape(-1), yy.reshape(-1), zz.reshape(-1)]
    foo = pv.PolyData(points)
    foo.rotate_z(36.6)
    return foo.points


# Get the points as a 2D NumPy array (N by 3)
points = make_point_set()
points[0:5, :]

pyvista_ndarray([[ -34.71943671, -281.07091791,    1.8127684 ],
                 [ -23.93431169, -273.06117719,    2.33592346],
                 [ -16.54269672, -267.57167946,    2.75042917],
                 [  -3.27044266, -257.71483371,    3.61029187],
                 [   6.2556755 , -250.64011401,    4.31540067]])

import matplotlib.pyplot as plt

plt.figure(figsize=(10, 10))
plt.scatter(points[:, 0], points[:, 1], c=points[:, 2])
plt.axis("image")
plt.xlabel("X Coordinate")
plt.ylabel("Y Coordinate")
plt.show()

生成一个规则网格曲面 pv.StructuredGrid

# Once you've figured out your grid's dimensions, simple create the
# :class:`pyvista.StructuredGrid` as follows:

mesh = pv.StructuredGrid()
# Set the coordinates from the numpy array
mesh.points = points
# set the dimensions
mesh.dimensions = [29, 32, 1]

# and then inspect it!
mesh.plot(show_edges=True, show_grid=True, cpos="xy")

grid.plot(show_edges=True)

top = grid.points.copy()
bottom = grid.points.copy()
print(bottom[0:5,:])
#生成底面
bottom[:,-1] = -10.0 # Wherever you want the plane
print(bottom[0:5,:])
vol = pv.StructuredGrid()
#堆叠top , bottom
vol.points = np.vstack((top, bottom))
# [grid.x,grid.y,2]
vol.dimensions = [*grid.dimensions[0:2], 2]
vol.plot(show_edges=True)

[[-10.         -10.           0.99998766]
 [-10.          -9.75         0.98546793]
 [-10.          -9.5          0.9413954 ]
 [-10.          -9.25         0.87027587]
 [-10.          -9.           0.7753401 ]]
[[-10.   -10.   -10.  ]
 [-10.    -9.75 -10.  ]
 [-10.    -9.5  -10.  ]
 [-10.    -9.25 -10.  ]
 [-10.    -9.   -10.  ]]