/
geometric_objects.py
2400 lines (1903 loc) · 68.3 KB
/
geometric_objects.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
"""Provides an easy way of generating several geometric objects.
**CONTAINS**
ArrowSource
CylinderSource
SphereSource
PlaneSource
LineSource
CubeSource
ConeSource
DiscSource
PolygonSource
vtkPyramid
PlatonicSolidSource
SuperquadricSource
Text3DSource
as well as some pure-python helpers.
"""
import contextlib
from itertools import product
import numpy as np
import pyvista
from pyvista.core import _vtk_core as _vtk
from .arrays import _coerce_pointslike_arg
from .geometric_sources import (
ArrowSource,
BoxSource,
ConeSource,
CubeSource,
CylinderSource,
DiscSource,
LineSource,
MultipleLinesSource,
PlaneSource,
PlatonicSolidSource,
PolygonSource,
SphereSource,
SuperquadricSource,
Text3DSource,
translate,
)
with contextlib.suppress(ImportError):
from .geometric_sources import CapsuleSource
from .helpers import wrap
from .misc import check_valid_vector
NORMALS = {
'x': [1, 0, 0],
'y': [0, 1, 0],
'z': [0, 0, 1],
'-x': [-1, 0, 0],
'-y': [0, -1, 0],
'-z': [0, 0, -1],
}
def Capsule(
center=(0.0, 0.0, 0.0),
direction=(1.0, 0.0, 0.0),
radius=0.5,
cylinder_length=1.0,
resolution=30,
):
"""Create the surface of a capsule.
.. warning::
:func:`pyvista.Capsule` function rotates the :class:`pyvista.CapsuleSource` 's :class:`pyvista.PolyData` in its own way.
It rotates the :attr:`pyvista.CapsuleSource.output` 90 degrees in z-axis, translates and
orients the mesh to a new ``center`` and ``direction``.
.. note::
A class:`pyvista.CylinderSource` is used to generate the capsule mesh. For vtk versions
below 9.3, a class:`pyvista.CapsuleSource` is used instead. The mesh geometries are similar but
not identical.
.. versionadded:: 0.44.0
Parameters
----------
center : sequence[float], default: (0.0, 0.0, 0.0)
Location of the centroid in ``[x, y, z]``.
direction : sequence[float], default: (1.0, 0.0, 0.0)
Direction the capsule points to in ``[x, y, z]``.
radius : float, default: 0.5
Radius of the capsule.
cylinder_length : float, default: 1.0
Cylinder length of the capsule.
resolution : int, default: 30
Number of points on the circular face of the cylinder.
Returns
-------
pyvista.PolyData
Capsule surface.
See Also
--------
pyvista.Cylinder
Examples
--------
Create a capsule using default parameters.
>>> import pyvista as pv
>>> capsule = pv.Capsule()
>>> capsule.plot(show_edges=True)
"""
if pyvista.vtk_version_info >= (9, 3): # pragma: no cover
algo = CylinderSource(
center=center,
direction=direction,
radius=radius,
height=cylinder_length,
capping=True,
resolution=resolution,
)
algo.capsule_cap = True
else:
algo = CapsuleSource(
center=center,
direction=direction,
radius=radius,
cylinder_length=cylinder_length,
theta_resolution=resolution,
phi_resolution=resolution,
)
output = wrap(algo.output)
output.rotate_z(90, inplace=True)
translate(output, center, direction)
return output
def Cylinder(
center=(0.0, 0.0, 0.0),
direction=(1.0, 0.0, 0.0),
radius=0.5,
height=1.0,
resolution=100,
capping=True,
):
"""Create the surface of a cylinder.
.. warning::
:func:`pyvista.Cylinder` function rotates the :class:`pyvista.CylinderSource` 's :class:`pyvista.PolyData` in its own way.
It rotates the :attr:`pyvista.CylinderSource.output` 90 degrees in z-axis, translates and
orients the mesh to a new ``center`` and ``direction``.
See also :func:`pyvista.CylinderStructured`.
Parameters
----------
center : sequence[float], default: (0.0, 0.0, 0.0)
Location of the centroid in ``[x, y, z]``.
direction : sequence[float], default: (1.0, 0.0, 0.0)
Direction cylinder points to in ``[x, y, z]``.
radius : float, default: 0.5
Radius of the cylinder.
height : float, default: 1.0
Height of the cylinder.
resolution : int, default: 100
Number of points on the circular face of the cylinder.
capping : bool, default: True
Cap cylinder ends with polygons.
Returns
-------
pyvista.PolyData
Cylinder surface.
Examples
--------
>>> import pyvista as pv
>>> cylinder = pv.Cylinder(
... center=[1, 2, 3], direction=[1, 1, 1], radius=1, height=2
... )
>>> cylinder.plot(show_edges=True, line_width=5, cpos='xy')
>>> pl = pv.Plotter()
>>> _ = pl.add_mesh(
... pv.Cylinder(
... center=[1, 2, 3], direction=[1, 1, 1], radius=1, height=2
... ),
... show_edges=True,
... line_width=5,
... )
>>> pl.camera_position = "xy"
>>> pl.show()
The above examples are similar in terms of their behavior.
"""
algo = CylinderSource(
center=center,
direction=direction,
radius=radius,
height=height,
capping=capping,
resolution=resolution,
)
output = wrap(algo.output)
output.rotate_z(90, inplace=True)
translate(output, center, direction)
return output
def CylinderStructured(
radius=0.5,
height=1.0,
center=(0.0, 0.0, 0.0),
direction=(1.0, 0.0, 0.0),
theta_resolution=32,
z_resolution=10,
):
"""Create a cylinder mesh as a :class:`pyvista.StructuredGrid`.
The end caps are left open. This can create a surface mesh if a single
value for the ``radius`` is given or a 3D mesh if multiple radii are given
as a list/array in the ``radius`` argument.
Parameters
----------
radius : float | sequence[float], default: 0.5
Radius of the cylinder. If a sequence, then describes the
radial coordinates of the cells as a range of values as
specified by the ``radius``.
height : float, default: 1.0
Height of the cylinder along its Z-axis.
center : sequence[float], default: (0.0, 0.0, 0.0)
Location of the centroid in ``[x, y, z]``.
direction : sequence[float], default: (1.0, 0.0, 0.0)
Direction cylinder Z-axis in ``[x, y, z]``.
theta_resolution : int, default: 32
Number of points on the circular face of the cylinder.
Ignored if ``radius`` is an iterable.
z_resolution : int, default: 10
Number of points along the height (Z-axis) of the cylinder.
Returns
-------
pyvista.StructuredGrid
Structured cylinder.
Notes
-----
.. versionchanged:: 0.38.0
Prior to version 0.38, this method had incorrect results, producing
inconsistent number of points on the circular face of the cylinder.
Examples
--------
Default structured cylinder
>>> import pyvista as pv
>>> mesh = pv.CylinderStructured()
>>> mesh.plot(show_edges=True)
Structured cylinder with an inner radius of 1, outer of 2, with 5
segments.
>>> import numpy as np
>>> mesh = pv.CylinderStructured(radius=np.linspace(1, 2, 5))
>>> mesh.plot(show_edges=True)
"""
# Define grid in polar coordinates
r = np.array([radius]).ravel()
nr = len(r)
theta = np.linspace(0, 2 * np.pi, num=theta_resolution + 1)
radius_matrix, theta_matrix = np.meshgrid(r, theta)
# Transform to cartesian space
X = radius_matrix * np.cos(theta_matrix)
Y = radius_matrix * np.sin(theta_matrix)
# Make all the nodes in the grid
xx = np.array([X] * z_resolution).ravel()
yy = np.array([Y] * z_resolution).ravel()
dz = height / (z_resolution - 1)
zz = np.empty(yy.size)
zz = np.full((X.size, z_resolution), dz)
zz *= np.arange(z_resolution)
zz = zz.ravel(order='f')
# Create the grid
grid = pyvista.StructuredGrid()
grid.points = np.c_[xx, yy, zz]
grid.dimensions = [nr, theta_resolution + 1, z_resolution]
# Center at origin
grid.points -= np.array(grid.center)
# rotate initially to face +X direction
grid.rotate_y(90, inplace=True)
# rotate points 180 for compatibility with previous versions
grid.rotate_x(180, inplace=True)
# move to final position
translate(grid, center=center, direction=direction)
return grid
def Arrow(
start=(0.0, 0.0, 0.0),
direction=(1.0, 0.0, 0.0),
tip_length=0.25,
tip_radius=0.1,
tip_resolution=20,
shaft_radius=0.05,
shaft_resolution=20,
scale=None,
):
"""Create an arrow.
Parameters
----------
start : sequence[float], default: (0.0, 0.0, 0.0)
Start location in ``[x, y, z]``.
direction : sequence[float], default: (1.0, 0.0, 0.0)
Direction the arrow points to in ``[x, y, z]``.
tip_length : float, default: 0.25
Length of the tip.
tip_radius : float, default: 0.1
Radius of the tip.
tip_resolution : int, default: 20
Number of faces around the tip.
shaft_radius : float, default: 0.05
Radius of the shaft.
shaft_resolution : int, default: 20
Number of faces around the shaft.
scale : float | str, optional
Scale factor of the entire object, defaults to a scale of 1.
``'auto'`` scales to length of direction array.
Returns
-------
pyvista.PolyData
Arrow mesh.
Examples
--------
Plot a default arrow.
>>> import pyvista as pv
>>> mesh = pv.Arrow()
>>> mesh.plot(show_edges=True)
"""
arrow = ArrowSource(
tip_length=tip_length,
tip_radius=tip_radius,
tip_resolution=tip_resolution,
shaft_radius=shaft_radius,
shaft_resolution=shaft_resolution,
)
surf = arrow.output
if scale == 'auto':
scale = float(np.linalg.norm(direction))
if isinstance(scale, (float, int)):
surf.points *= scale
elif scale is not None:
raise TypeError("Scale must be either float, int or 'auto'.")
translate(surf, start, direction)
return surf
def Sphere(
radius=0.5,
center=(0.0, 0.0, 0.0),
direction=(0.0, 0.0, 1.0),
theta_resolution=30,
phi_resolution=30,
start_theta=0.0,
end_theta=360.0,
start_phi=0.0,
end_phi=180.0,
):
"""Create a sphere.
A sphere describes a 2D surface in comparison to
:func:`pyvista.SolidSphere`, which fills a 3D volume.
PyVista uses a convention where ``theta`` represents the azimuthal
angle (similar to degrees longitude on the globe) and ``phi``
represents the polar angle (similar to degrees latitude on the
globe). In contrast to latitude on the globe, here
``phi`` is 0 degrees at the North Pole and 180 degrees at the South
Pole. ``phi=0`` is on the positive z-axis by default.
``theta=0`` is on the positive x-axis by default.
Parameters
----------
radius : float, default: 0.5
Sphere radius.
center : sequence[float], default: (0.0, 0.0, 0.0)
Center coordinate vector in ``[x, y, z]``.
direction : sequence[float], default: (0.0, 0.0, 1.0)
Direction coordinate vector in ``[x, y, z]`` pointing from ``center`` to
the sphere's north pole at zero degrees ``phi``.
theta_resolution : int, default: 30
Set the number of points in the azimuthal direction (ranging
from ``start_theta`` to ``end_theta``).
phi_resolution : int, default: 30
Set the number of points in the polar direction (ranging from
``start_phi`` to ``end_phi``).
start_theta : float, default: 0.0
Starting azimuthal angle in degrees ``[0, 360]``.
end_theta : float, default: 360.0
Ending azimuthal angle in degrees ``[0, 360]``.
start_phi : float, default: 0.0
Starting polar angle in degrees ``[0, 180]``.
end_phi : float, default: 180.0
Ending polar angle in degrees ``[0, 180]``.
Returns
-------
pyvista.PolyData
Sphere mesh.
See Also
--------
pyvista.Icosphere : Sphere created from projection of icosahedron.
pyvista.SolidSphere : Sphere that fills 3D space.
Examples
--------
Create a sphere using default parameters.
>>> import pyvista as pv
>>> sphere = pv.Sphere()
>>> sphere.plot(show_edges=True)
Create a quarter sphere by setting ``end_theta``.
>>> sphere = pv.Sphere(end_theta=90)
>>> out = sphere.plot(show_edges=True)
Create a hemisphere by setting ``end_phi``.
>>> sphere = pv.Sphere(end_phi=90)
>>> out = sphere.plot(show_edges=True)
"""
sphere = SphereSource(
radius=radius,
theta_resolution=theta_resolution,
phi_resolution=phi_resolution,
start_theta=start_theta,
end_theta=end_theta,
start_phi=start_phi,
end_phi=end_phi,
)
surf = sphere.output
surf.rotate_y(90, inplace=True)
translate(surf, center, direction)
return surf
def SolidSphere(
outer_radius=0.5,
inner_radius=0.0,
radius_resolution=5,
start_theta=0.0,
end_theta=None,
theta_resolution=30,
start_phi=0.0,
end_phi=None,
phi_resolution=30,
center=(0.0, 0.0, 0.0),
direction=(0.0, 0.0, 1.0),
radians=False,
tol_radius=1.0e-8,
tol_angle=None,
):
"""Create a solid sphere.
A solid sphere fills space in 3D in comparison to
:func:`pyvista.Sphere`, which is a 2D surface.
This function uses a linear sampling of each spherical
coordinate, whereas :func:`pyvista.SolidSphereGeneric`
allows for nonuniform sampling. Angles are by default
specified in degrees.
PyVista uses a convention where ``theta`` represents the azimuthal
angle (similar to degrees longitude on the globe) and ``phi``
represents the polar angle (similar to degrees latitude on the
globe). In contrast to latitude on the globe, here
``phi`` is 0 degrees at the North Pole and 180 degrees at the South
Pole. ``phi=0`` is on the positive z-axis by default.
``theta=0`` is on the positive x-axis by default.
While values for theta can be any value with a maximum span of
360 degrees, large magnitudes may result in problems with endpoint
overlap detection.
Parameters
----------
outer_radius : float, default: 0.5
Outer radius of sphere. Must be non-negative.
inner_radius : float, default: 0.0
Inner radius of sphere. Must be non-negative
and smaller than ``outer_radius``.
radius_resolution : int, default: 5
Number of points in radial direction.
start_theta : float, default: 0.0
Starting azimuthal angle.
end_theta : float, default: 360.0
Ending azimuthal angle.
``end_theta`` must be greater than ``start_theta``.
theta_resolution : int, default: 30
Number of points in ``theta`` direction.
start_phi : float, default: 0.0
Starting polar angle.
``phi`` must lie between 0 and 180 in degrees.
end_phi : float, default: 180.0
Ending polar angle.
``phi`` must lie between 0 and 180 in degrees.
``end_phi`` must be greater than ``start_phi``.
phi_resolution : int, default: 30
Number of points in ``phi`` direction,
inclusive of polar axis, i.e. ``phi=0`` and ``phi=180``
in degrees, if applicable.
center : sequence[float], default: (0.0, 0.0, 0.0)
Center coordinate vector in ``[x, y, z]``.
direction : sequence[float], default: (0.0, 0.0, 1.0)
Direction coordinate vector in ``[x, y, z]`` pointing from ``center`` to
the sphere's north pole at zero degrees ``phi``.
radians : bool, default: False
Whether to use radians for ``theta`` and ``phi``. Default is degrees.
tol_radius : float, default: 1.0e-8
Absolute tolerance for endpoint detection for ``radius``.
tol_angle : float, optional
Absolute tolerance for endpoint detection
for ``phi`` and ``theta``. Unit is determined by choice
of ``radians`` parameter. Default is 1.0e-8 degrees or
1.0e-8 degrees converted to radians.
Returns
-------
pyvista.UnstructuredGrid
Solid sphere mesh.
See Also
--------
pyvista.Sphere: Sphere that describes outer 2D surface.
pyvista.SolidSphereGeneric: Uses more flexible parameter definition.
Examples
--------
Create a solid sphere.
>>> import pyvista as pv
>>> import numpy as np
>>> solid_sphere = pv.SolidSphere()
>>> solid_sphere.plot(show_edges=True)
A solid sphere is 3D in comparison to the 2d :func:`pyvista.Sphere`.
Generate a solid hemisphere to see the internal structure.
>>> isinstance(solid_sphere, pv.UnstructuredGrid)
True
>>> partial_solid_sphere = pv.SolidSphere(
... start_theta=180, end_theta=360
... )
>>> partial_solid_sphere.plot(show_edges=True)
To see the cell structure inside the solid sphere,
only 1/4 of the sphere is generated. The cells are exploded
and colored by radial position.
>>> partial_solid_sphere = pv.SolidSphere(
... start_theta=180,
... end_theta=360,
... start_phi=0,
... end_phi=90,
... radius_resolution=5,
... theta_resolution=8,
... phi_resolution=8,
... )
>>> partial_solid_sphere["cell_radial_pos"] = np.linalg.norm(
... partial_solid_sphere.cell_centers().points, axis=-1
... )
>>> partial_solid_sphere.explode(1).plot()
"""
if end_theta is None:
end_theta = 2 * np.pi if radians else 360.0
if end_phi is None:
end_phi = np.pi if radians else 180.0
radius = np.linspace(inner_radius, outer_radius, radius_resolution)
theta = np.linspace(start_theta, end_theta, theta_resolution)
phi = np.linspace(start_phi, end_phi, phi_resolution)
return SolidSphereGeneric(
radius,
theta,
phi,
center,
direction,
radians=radians,
tol_radius=tol_radius,
tol_angle=tol_angle,
)
def SolidSphereGeneric(
radius=None,
theta=None,
phi=None,
center=(0.0, 0.0, 0.0),
direction=(0.0, 0.0, 1.0),
radians=False,
tol_radius=1.0e-8,
tol_angle=None,
):
"""Create a solid sphere with flexible sampling.
A solid sphere fills space in 3D in comparison to
:func:`pyvista.Sphere`, which is a 2D surface.
This function allows user defined sampling of each spherical
coordinate, whereas :func:`pyvista.SolidSphere`
only allows linear sampling. Angles are by default
specified in degrees.
PyVista uses a convention where ``theta`` represents the azimuthal
angle (similar to degrees longitude on the globe) and ``phi``
represents the polar angle (similar to degrees latitude on the
globe). In contrast to latitude on the globe, here
``phi`` is 0 degrees at the North Pole and 180 degrees at the South
Pole. ``phi=0`` is on the positive z-axis by default.
``theta=0`` is on the positive x-axis by default.
Parameters
----------
radius : sequence[float], optional
A monotonically increasing sequence of values specifying radial
points. Must have at least two points and be non-negative.
theta : sequence[float], optional
A monotonically increasing sequence of values specifying ``theta``
points. Must have at least two points. Can have any value as long
as range is within 360 degrees. Large magnitudes may result in
problems with endpoint overlap detection.
phi : sequence[float], optional
A monotonically increasing sequence of values specifying ``phi``
points. Must have at least two points. Must be between
0 and 180 degrees.
center : sequence[float], default: (0.0, 0.0, 0.0)
Center coordinate vector in ``[x, y, z]``.
direction : sequence[float], default: (0.0, 0.0, 1.0)
Direction coordinate vector in ``[x, y, z]`` pointing from ``center`` to
the sphere's north pole at zero degrees ``phi``.
radians : bool, default: False
Whether to use radians for ``theta`` and ``phi``. Default is degrees.
tol_radius : float, default: 1.0e-8
Absolute tolerance for endpoint detection for ``radius``.
tol_angle : float, optional
Absolute tolerance for endpoint detection
for ``phi`` and ``theta``. Unit is determined by choice
of ``radians`` parameter. Default is 1.0e-8 degrees or
1.0e-8 degrees converted to radians.
Returns
-------
pyvista.UnstructuredGrid
Solid sphere mesh.
See Also
--------
pyvista.SolidSphere: Sphere creation using linear sampling.
pyvista.Sphere: Sphere that describes outer 2D surface.
Examples
--------
Linearly sampling spherical coordinates does not lead to
cells of all the same size at each radial position.
Cells near the poles have smaller sizes.
>>> import pyvista as pv
>>> import numpy as np
>>> solid_sphere = pv.SolidSphereGeneric(
... radius=np.linspace(0, 0.5, 2),
... theta=np.linspace(180, 360, 30),
... phi=np.linspace(0, 180, 30),
... )
>>> solid_sphere = solid_sphere.compute_cell_sizes()
>>> solid_sphere.plot(
... scalars="Volume", show_edges=True, clim=[3e-5, 5e-4]
... )
Sampling the polar angle in a nonlinear manner allows for consistent cell volumes. See
`Sphere Point Picking <https://mathworld.wolfram.com/SpherePointPicking.html>`_.
>>> phi = np.rad2deg(np.arccos(np.linspace(1, -1, 30)))
>>> solid_sphere = pv.SolidSphereGeneric(
... radius=np.linspace(0, 0.5, 2),
... theta=np.linspace(180, 360, 30),
... phi=phi,
... )
>>> solid_sphere = solid_sphere.compute_cell_sizes()
>>> solid_sphere.plot(
... scalars="Volume", show_edges=True, clim=[3e-5, 5e-4]
... )
"""
if radius is None:
radius = np.linspace(0, 0.5, 5)
radius = np.asanyarray(radius)
# Default tolerance from user is set in degrees
# But code is in radians.
if tol_angle is None:
tol_angle = np.deg2rad(1e-8)
elif not radians:
tol_angle = np.deg2rad(tol_angle)
if theta is None:
theta = np.linspace(0, 2 * np.pi, 30)
else:
theta = np.asanyarray(theta) if radians else np.deg2rad(theta)
if phi is None:
phi = np.linspace(0, np.pi, 30)
else:
phi = np.asanyarray(phi) if radians else np.deg2rad(phi)
# Hereafter all degrees are in radians
# radius, phi, theta are now np.ndarrays
nr = len(radius)
ntheta = len(theta)
nphi = len(phi)
if nr < 2:
raise ValueError("radius resolution must be 2 or more")
if ntheta < 2:
raise ValueError("theta resolution must be 2 or more")
if nphi < 2:
raise ValueError("phi resolution must be 2 or more")
def _is_sorted(a):
return np.all(a[:-1] < a[1:])
if not _is_sorted(radius):
raise ValueError("radius is not monotonically increasing")
if not _is_sorted(theta):
raise ValueError("theta is not monotonically increasing")
if not _is_sorted(phi):
raise ValueError("phi is not monotonically increasing")
def _greater_than_equal_or_close(value1, value2, atol):
return value1 >= value2 or np.isclose(value1, value2, rtol=0.0, atol=atol)
def _less_than_equal_or_close(value1, value2, atol):
return value1 <= value2 or np.isclose(value1, value2, rtol=0.0, atol=atol)
if not _greater_than_equal_or_close(radius[0], 0.0, tol_radius):
raise ValueError("minimum radius cannot be negative")
# range of theta cannot be greater than 360 degrees
if not _less_than_equal_or_close(theta[-1] - theta[0], 2 * np.pi, tol_angle):
max_angle = "2 * np.pi" if radians else "360 degrees"
raise ValueError(f"max theta and min theta must be within {max_angle}")
if not _greater_than_equal_or_close(phi[0], 0.0, tol_angle):
raise ValueError("minimum phi cannot be negative")
if not _less_than_equal_or_close(phi[-1], np.pi, tol_angle):
max_angle = "np.pi" if radians else "180 degrees"
raise ValueError(f"maximum phi cannot be > {max_angle}")
def _spherical_to_cartesian(r, phi, theta):
"""Convert spherical coordinate sequences to a ``(n,3)`` Cartesian coordinate array.
Parameters
----------
r : sequence[float]
Ordered sequence of floats of radii.
phi : sequence[float]
Ordered sequence of floats for phi direction.
theta : sequence[float]
Ordered sequence of floats for theta direction.
Returns
-------
np.ndarray
``(n, 3)`` Cartesian coordinate array.
"""
r, phi, theta = np.meshgrid(r, phi, theta, indexing='ij')
x, y, z = pyvista.spherical_to_cartesian(r, phi, theta)
return np.vstack((x.ravel(), y.ravel(), z.ravel())).transpose()
points = []
npoints_on_axis = 0
if np.isclose(radius[0], 0.0, rtol=0.0, atol=tol_radius):
points.append([0.0, 0.0, 0.0])
include_origin = True
nr = nr - 1
radius = radius[1:]
npoints_on_axis += 1
else:
include_origin = False
if np.isclose(theta[-1] - theta[0], 2 * np.pi, rtol=0.0, atol=tol_angle):
duplicate_theta = True
theta = theta[:-1]
else:
duplicate_theta = False
if np.isclose(phi[0], 0.0, rtol=0.0, atol=tol_angle):
points.extend(_spherical_to_cartesian(radius, 0.0, theta[0]))
positive_axis = True
phi = phi[1:]
nphi = nphi - 1
npoints_on_axis += nr
else:
positive_axis = False
npoints_on_pos_axis = npoints_on_axis
if np.isclose(phi[-1], np.pi, rtol=0.0, atol=tol_angle):
points.extend(_spherical_to_cartesian(radius, np.pi, theta[0]))
negative_axis = True
phi = phi[:-1]
nphi = nphi - 1
npoints_on_axis += nr
else:
negative_axis = False
# rest of points with theta changing quickest
for ir, iphi in product(radius, phi):
points.extend(_spherical_to_cartesian(ir, iphi, theta))
cells = []
celltypes = []
def _index(ir, iphi, itheta):
"""Index for points not on axis.
Values of ir and phi here are relative to the first nonaxis values.
"""
if duplicate_theta:
ntheta_ = ntheta - 1
itheta = itheta % ntheta_
else:
ntheta_ = ntheta
return npoints_on_axis + ir * nphi * ntheta_ + iphi * ntheta_ + itheta
if include_origin:
# First make the tetras that form with origin and axis point
# origin is 0
# first axis point is 1
# other points at first phi position off axis
if positive_axis:
for itheta in range(ntheta - 1):
cells.append(4)
cells.extend([0, 1, _index(0, 0, itheta), _index(0, 0, itheta + 1)])
celltypes.append(pyvista.CellType.TETRA)
# Next tetras that form with origin and bottom axis point
# origin is 0
# axis point is first in negative dir
# other points at last phi position off axis
if negative_axis:
for itheta in range(ntheta - 1):
cells.append(4)
cells.extend(
[
0,
npoints_on_pos_axis,
_index(0, nphi - 1, itheta + 1),
_index(0, nphi - 1, itheta),
],
)
celltypes.append(pyvista.CellType.TETRA)
# Pyramids that form to origin but without an axis point
for iphi, itheta in product(range(nphi - 1), range(ntheta - 1)):
cells.append(5)
cells.extend(
[
_index(0, iphi, itheta),
_index(0, iphi, itheta + 1),
_index(0, iphi + 1, itheta + 1),
_index(0, iphi + 1, itheta),
0,
],
)
celltypes.append(pyvista.CellType.PYRAMID)
# Wedges form between two r levels at first and last phi position
# At each r level, the triangle is formed with axis point, two theta positions
# First go upwards
if positive_axis:
for ir, itheta in product(range(nr - 1), range(ntheta - 1)):
axis0 = ir + 1 if include_origin else ir
axis1 = ir + 2 if include_origin else ir + 1
cells.append(6)
cells.extend(
[
axis0,
_index(ir, 0, itheta + 1),
_index(ir, 0, itheta),
axis1,
_index(ir + 1, 0, itheta + 1),
_index(ir + 1, 0, itheta),
],
)
celltypes.append(pyvista.CellType.WEDGE)
# now go downwards
if negative_axis:
for ir, itheta in product(range(nr - 1), range(ntheta - 1)):
axis0 = npoints_on_pos_axis + ir
axis1 = npoints_on_pos_axis + ir + 1
cells.append(6)
cells.extend(
[
axis0,
_index(ir, nphi - 1, itheta),
_index(ir, nphi - 1, itheta + 1),
axis1,
_index(ir + 1, nphi - 1, itheta),
_index(ir + 1, nphi - 1, itheta + 1),
],
)
celltypes.append(pyvista.CellType.WEDGE)
# Form Hexahedra
# Hexahedra form between two r levels and two phi levels and two theta levels
# Order by r levels
for ir, iphi, itheta in product(range(nr - 1), range(nphi - 1), range(ntheta - 1)):
cells.append(8)
cells.extend(
[
_index(ir, iphi, itheta),
_index(ir, iphi + 1, itheta),
_index(ir, iphi + 1, itheta + 1),