Post-processing not plotting results

[germa89]

"""
.. _ref_tors_load:
==============================================
Torsional load on a bar using SURF154 elements
==============================================
This Ansys PyMAPDL script builds a bar and applies torque to it using
SURF154 elements. This is a static analysis example.
"""

##############################################################################
# Script initialization
# ---------------------

import os

import numpy as np

from ansys.mapdl.core import launch_mapdl

# start Ansys in the current working directory with default jobname "file"
mapdl = launch_mapdl(start_instance=False)


##############################################################################
# Define cylinder and mesh parameters

torque = 100
radius = 2
h_tip = 2
height = 20
elemsize = 0.5
pi = np.arccos(-1)
force = 100 / radius
pressure = force / (h_tip * 2 * np.pi * radius)

##############################################################################
# Model creation
# --------------

# Define higher-order SOLID186
# Define surface effect elements SURF154 to apply torque
# as a tangential pressure
mapdl.prep7()
mapdl.et(1, 186)
mapdl.et(2, 154)
mapdl.r(1)
mapdl.r(2)

##############################################################################
# Aluminum properties (or something)
mapdl.mp("ex", 1, 10e6)
mapdl.mp("nuxy", 1, 0.3)
mapdl.mp("dens", 1, 0.1 / 386.1)
mapdl.mp("dens", 2, 0)

# Simple cylinder
for i in range(4):
    mapdl.cylind(radius, "", "", height, 90 * (i - 1), 90 * i)

mapdl.nummrg("kp")

# interactive volume plot (optional)
mapdl.vplot()


##############################################################################
# Mesh cylinder
mapdl.lsel("s", "loc", "x", 0)
mapdl.lsel("r", "loc", "y", 0)
mapdl.lsel("r", "loc", "z", 0, height - h_tip)
mapdl.lesize("all", elemsize * 2)
mapdl.mshape(0)
mapdl.mshkey(1)
mapdl.esize(elemsize)
mapdl.allsel("all")
mapdl.vsweep("ALL")
mapdl.csys(1)
mapdl.asel("s", "loc", "z", "", height - h_tip + 0.0001)
mapdl.asel("r", "loc", "x", radius)
mapdl.local(11, 1)
mapdl.csys(0)
mapdl.aatt(2, 2, 2, 11)
mapdl.amesh("all")
mapdl.finish()

# plot elements
mapdl.eplot()

##############################################################################
# Solution
# --------

mapdl.slashsolu()  # Using Slash instead of / due to duplicate SOLU command
mapdl.antype("static", "new")
mapdl.eqslv("pcg", 1e-8)

# Apply tangential pressure
mapdl.esel("s", "type", "", 2)
mapdl.sfe("all", 2, "pres", "", pressure)

# Constrain bottom of cylinder/rod
mapdl.asel("s", "loc", "z", 0)
mapdl.nsla("s", 1)

mapdl.d("all", "all")
mapdl.allsel()
mapdl.psf("pres", "", 2)
mapdl.pbc("u", 1)
mapdl.solve()


##############################################################################
# Alternatively, you can access the same results directly from MAPDL
# using the :attr:`Mapdl.post_processing <ansys.mapdl.core.Mapdl.post_processing>`
# attribute:

# Enter post-processor
mapdl.post1()

mapdl.set(1, 1)
mapdl.post_processing.plot_nodal_displacement(cmap="bwr")
mapdl.post_processing.plot_nodal_component_stress("x", cmap="bwr")
mapdl.post_processing.plot_nodal_eqv_stress(cmap="bwr")

the plots are empty:

[germa89]

It seems the problem is with the masking in _plot_point_scalars.

mask = self.selected_nodes

[germa89]

It seems the problem is with the masking in _plot_point_scalars.

mask = self.selected_nodes

It is not that.... I think there is a miss matching between the UnstructuredGrid and the data returned by MAPDL.

For example:

>>> self._mapdl.mesh._surf # Used for plotting
PolyData (0x1628e8640)
  N Cells:    1272
  N Points:   714
  N Strips:   0
  X Bounds:   -2.000e+00, 2.000e+00
  Y Bounds:   -2.000e+00, 2.000e+00
  Z Bounds:   0.000e+00, 2.000e+01
  N Arrays:   11
>>> self._mapdl.mesh.grid # the real mesh?
UnstructuredGrid (0x162930b20)
  N Cells:    2080
  N Points:   7217
  X Bounds:   -2.000e+00, 2.000e+00
  Y Bounds:   -2.000e+00, 2.000e+00
  Z Bounds:   0.000e+00, 2.000e+01
  N Arrays:   10

surf is the "outlayer" of the plot. It is useful because it reduces its size. However, the data input in here is all the nodes.

Something is made here to match both. But probably is not longer valid since the latest PyVista changes. Probably because of changing the way the points/cells are ordered internally.