[PyVista]調査メモ

はじめに

PyVistaの調査メモ

環境

Window10環境で実行しました。

PS C:\> python -V
Python 3.9.5
PS C:\> pip list | Select-String "PyVista"

pyvista               0.31.3
pyvistaqt             0.5.0

ウィンドウを開きシリンダーオブジェクトを描画

import pyvista as pv
import numpy as np

targetImage = [ "image0.png" , "image1.png"]
surf = pv.Cylinder()
tex = pv.numpy_to_texture(targetImage[0])
surf.plot(texture=tex)

テクスチャ用の画像

シリンダーオブジェクトを画像出力

実行結果

png画像出力

import pyvista as pv
import numpy as np

targetImage = [ "image0.png" , "image1.png" ]
#surf = pv.Cylinder()
surf = pv.Cylinder(np.array([0, 0, 0]), np.array([0, 0, 1]), 1.0, 1.0)
"""
arg1: 座標 Location of the centroid in [x, y, z]
arg2: 向き Direction cylinder points to in [x, y, z]
arg3: 円の大きさ
arg4: 円柱の高さ 
"""
tex = pv.numpy_to_texture(targetImage[1])
plotter = pv.Plotter(off_screen=True)
plotter.add_mesh(surf , texture=tex, point_size=5.0)
plotter.screenshot('output.png')

イメージファイルの読み込み

読み込んだ画像を描画します

参考

実行結果

import pyvista as pv

targetImage = [ "image0.png" , "image1.png" ]
mesh = pv.read(targetImage[1])
mesh.plot(rgb=True, cpos="xy")

オブジェクトを2つ配置し画像出力

実行結果

import pyvista as pv
import numpy as np
plotter = pv.Plotter(off_screen=True, window_size=(400,400))

obj1 = pv.Cylinder(np.array([0, 0, 0]), np.array([0, 0, 1]), 1.0, 1.0)
plotter.add_mesh(obj1 ,color="green", show_edges=True)

obj2 = pv.Cylinder(np.array([0, 0, 1]), np.array([1, 0, 1]), 0.5, 3.0)
plotter.add_mesh(obj2 ,color="red", show_edges=True)

plotter.screenshot('output.png')

ドーナツ型オブジェクト

参照

実行結果

ウィンドウ描画

import pyvista as pv
pv.CylinderStructured(
        center=(0.0, 0.0, 0.0), 
        direction=(1.0, 0.0, 0.0), 
        radius=[2, 2.5], 
        height=3.0
    ).plot(show_edges=True)

画像出力

import pyvista as pv
obj = pv.CylinderStructured(
        center=(0.0, 0.0, 0.0), 
        direction=(1.0, 0.0, 0.0), 
        radius=[2, 2.5], 
        height=3.0
    )
plotter = pv.Plotter(off_screen=True, window_size=(400,400))
plotter.add_mesh(obj)
plotter.screenshot('output.png')

実行結果（背景透過）

画像出力(背景透明)

import pyvista as pv
pv.rcParams['transparent_background'] = True
obj = pv.CylinderStructured(
        center=(0.0, 0.0, 0.0), 
        direction=(1.0, 0.0, 0.0), 
        radius=[2, 2.5], 
        height=3.0
    )
plotter = pv.Plotter(off_screen=True, window_size=(400,400))
plotter.add_mesh(obj)
plotter.screenshot('output.png')

ブール演算

オブジェクトが重なる箇所をマスクする　※勉強中※

参考

実行結果

import pyvista as pv
import numpy as np
def make_cube():
    x = np.linspace(-0.5, 0.5, 25)
    grid = pv.StructuredGrid(*np.meshgrid(x, x, x))
    return grid.extract_surface().triangulate()

# Create to example PolyData meshes for boolean operations
sphere = pv.Sphere(radius=0.65, center=(0, 0, 0))

cube = make_cube()
union = sphere.boolean_union(cube)
p = pv.Plotter()
p.add_mesh(union,  opacity=0.5, show_edges=True, color=True)
p.show()

【NG例】オブジェクト同士が重なっていないとエラーになる

【NG例】

import pyvista as pv
import numpy as np
def make_cube():
    x = np.linspace(-0.5, 0.5, 25)
    grid = pv.StructuredGrid(*np.meshgrid(x, x, x))
    return grid.extract_surface().triangulate()

# Create to example PolyData meshes for boolean operations
sphere = pv.Sphere(radius=0.65, center=(3, 3, 3))

cube = make_cube()
union = sphere.boolean_union(cube)
p = pv.Plotter()
p.add_mesh(union,  opacity=0.5, show_edges=True, color=True)
p.show()

エラーメッセージ

PS C:\Users\user01\pyvista> python .\booltest.py
2021-08-07 17:38:47.837 (   0.135s) [                ]    vtkPointLocator.cxx:845    ERR| vtkPointLocator (000002DABCA16130): No points to subdivide
ERROR:root:No points to subdivide
2021-08-07 17:38:47.839 (   0.136s) [                ]vtkIntersectionPolyData:2410  WARN| No Intersection between objects
2021-08-07 17:38:47.840 (   0.137s) [                ]vtkDistancePolyDataFilt:82     ERR| vtkDistancePolyDataFilter (000002DAAB083FE0): No points/cells to operate on
ERROR:root:No points/cells to operate on
2021-08-07 17:38:47.840 (   0.138s) [                ]vtkDistancePolyDataFilt:82     ERR| vtkDistancePolyDataFilter (000002DAAB083FE0): No points/cells to operate on
ERROR:root:No points/cells to operate on
Traceback (most recent call last):
  File "C:\Users\user01\pyvista\booltest.py", line 32, in <module>
    p.add_mesh(union,  opacity=0.5, show_edges=True, color=True)
  File "C:\Users\user01\AppData\Local\Programs\Python\Python39\lib\site-packages\pyvista\plotting\plotting.py", line 1480, in add_mesh
    raise ValueError('Empty meshes cannot be plotted. Input mesh has zero points.')
ValueError: Empty meshes cannot be plotted. Input mesh has zero points.
PS C:\Users\user01\pyvista>

ブール演算：検証① → 失敗

ブール演算の前準備として、2つのオブジェクトを重なるように配置する

import pyvista as pv
pv.rcParams['transparent_background'] = True

obj0 = pv.Cube(
        center=(0.0, 0.0, 0.0), 
        x_length=1.0, 
        y_length=0.1, 
        z_length=1.0, 
        bounds=None
    )
obj2 = pv.Cylinder(
        center=(0.0, -0.05, 0.0), 
        direction=(0.0, 1.0, 0.0),
        radius=0.4, 
        height=0.4
    )

plotter = pv.Plotter(off_screen=False, window_size=(400,400))
plotter.camera.position    = (6.0, 6.0, 6.0)

plotter.add_mesh(obj0 ,color="FFFFFF", show_edges=True)
plotter.add_mesh(obj2 ,color="red", show_edges=True)

plotter.show()

これをブール演算するとエラー発生　※原因調査中※

エラーになる

import pyvista as pv
pv.rcParams['transparent_background'] = True

obj0 = pv.Cube(
        center=(0.0, 0.0, 0.0), 
        x_length=1.0, 
        y_length=0.1, 
        z_length=1.0, 
        bounds=None
    )

obj2 = pv.Cylinder(
        center=(0.0, -0.05, 0.0), 
        direction=(0.0, 1.0, 0.0),
        radius=0.4, 
        height=0.4
    )

union = obj2.boolean_union(obj0)

plotter = pv.Plotter(off_screen=False, window_size=(400,400))
plotter.camera.position    = (6.0, 6.0, 6.0)
plotter.add_mesh(union ,color="FFFFFF", show_edges=True)
plotter.show()

PS C:\Users\user01\python\pyvista> python .\test2.py
2021-08-08 06:29:41.575 (   0.138s) [                ]    vtkPointLocator.cxx:845    ERR| vtkPointLocator (000002BD6BE50CB0): No points to subdivide
ERROR:root:No points to subdivide
2021-08-08 06:29:41.577 (   0.139s) [                ]vtkIntersectionPolyData:2410  WARN| No Intersection between objects
2021-08-08 06:29:41.577 (   0.139s) [                ]vtkDistancePolyDataFilt:82     ERR| vtkDistancePolyDataFilter (000002BD5AD8F060): No points/cells to operate on
ERROR:root:No points/cells to operate on
2021-08-08 06:29:41.578 (   0.140s) [                ]vtkDistancePolyDataFilt:82     ERR| vtkDistancePolyDataFilter (000002BD5AD8F060): No points/cells to operate on
ERROR:root:No points/cells to operate on
Traceback (most recent call last):
  File "C:\Users\user01\python\pyvista\test2.py", line 25, in <module>
    plotter.add_mesh(union ,color="FFFFFF", show_edges=True)
  File "C:\Users\zgw42\AppData\Local\Programs\Python\Python39\lib\site-packages\pyvista\plotting\plotting.py", line 1480, in add_mesh
    raise ValueError('Empty meshes cannot be plotted. Input mesh has zero points.')
ValueError: Empty meshes cannot be plotted. Input mesh has zero points.
PS C:\Users\user01\python\pyvista>

（エラー対策わかったら追記します）

穴形状のオブジェクトを作ってみる

PyVistaの習得できた範囲で穴形状のオブジェクトを作ってみます。ブール演算は理解できてないので、壁に穴が空いた表現は、透過画像で代用します。中央に透過率100%の円がある画像を用意します。

実行結果

import pyvista as pv

pv.rcParams['transparent_background'] = True
targetImage = [ "image0.png" , "image1.png","image2.png" ]
tex = pv.numpy_to_texture(targetImage[2])

obj0 = pv.Plane(
        center=(0, 0, 0),
        direction=(0, 1, 0),
        i_size=1,
        j_size=1,
        i_resolution=20,
        j_resolution=20
    )
obj1 = pv.CylinderStructured(
        center=(0.0, -0.51, 0.0), 
        direction=(0.0, 1.0, 0.0), 
        radius=[0.3, 0.4], 
        height=1.0
    )

#plotter = pv.Plotter(off_screen=True, window_size=(400,400))
plotter = pv.Plotter(off_screen=False, window_size=(400,400))
plotter.camera.position    = (6.0, 6.0, 6.0)

plotter.add_mesh(obj0 ,color="FFFFFF", show_edges=False , texture=tex)
plotter.add_mesh(obj1 ,color="green", show_edges=True)

#plotter.screenshot('output.png')
plotter.show()

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PyVistaまだまだわかってないです。調査はつづく