Interactive plotting

When generating geometry from scratch within MAPDL, it is often necessary to plot the geometry, such as key points, lines, areas, and volumes. PyMAPDL supports plotting basic CAD using VTK. The Mapdl class leverages the existing MAPDL commands by providing the following functions, which transfer the geometry to Python to visualize it:

• Mapdl.kplot()

• Mapdl.vplot()

• Mapdl.eplot()).

These methods rely on the ansys.mapdl.core.plotting.visualizer.MapdlPlotter method. Combined with the MAPDL geometry commands, you can generate and visualize geometry from scratch without opening the GUI using the open_gui() method.

Line plotting

You plot lines within Python using the Mapdl.lplot() method:

>>> from ansys.mapdl.core import launch_mapdl
>>> import numpy as np
>>> mapdl = launch_mapdl()

# Create a rectangle with a few holes
>>> mapdl.prep7()
>>> rect_anum = mapdl.blc4(width=1, height=0.2)

# Create several circles in the middle in the rectangle
>>> for x in np.linspace(0.1, 0.9, 8):
...     mapdl.cyl4(x, 0.1, 0.025)
...

# Generate a line plot
>>> mapdl.lplot(color_lines=True, cpos="xy")

Line plot from MAPDL using PyMAPDL and PyVista

Area and volume plotting

You can using Boolean operations to obtain more complex geometry and visualize them using the Mapdl.vplot() method. This example cuts the initial area with the eight circles and then extrudes it.

>>> plate_holes = mapdl.asba(rect_anum, "all")

# Extrude this area
>>> mapdl.vext(plate_holes, dz=0.1)
>>> mapdl.vplot()

Volume Plot from MAPDL using PyMAPDL and PyVista

Node and element plotting

You can plot nodes and elements directly from the instance of the Mapdl class. This code defines some element types, performs meshing, and then displays the mesh:

>>> mapdl.et(1, "SOLID186")
>>> mapdl.vsweep("ALL")
>>> mapdl.esize(0.1)
>>> mapdl.eplot()

Element Plot from MAPDL using PyMAPDL and PyVista

Plotting non-interactively using MAPDL

You can also plot using MAPDL’s native plotting tools. To use the native tools, pass vtk=False when running plotting commands such as the Mapdl.aplot and Mapdl.eplot methods. Plots are generated within MAPDL and then shown using Matplotlib.

Start PyMAPDL

>>> from ansys.mapdl.core import launch_mapdl
>>> mapdl = launch_mapdl()

Create a square area using key points

>>> mapdl.prep7()
>>> mapdl.k(1, 0, 0, 0)
>>> mapdl.k(2, 1, 0, 0)
>>> mapdl.k(3, 1, 1, 0)
>>> mapdl.k(4, 0, 1, 0)
>>> mapdl.l(1, 2)
>>> mapdl.l(2, 3)
>>> mapdl.l(3, 4)
>>> mapdl.l(4, 1)
>>> mapdl.al(1, 2, 3, 4)

Set the view to “isometric”

>>> mapdl.view(1, 1, 1, 1)
>>> mapdl.pnum("kp", 1)  # enable keypoint numbering
>>> mapdl.pnum("line", 1)  # enable line numbering

Each of these creates a Matplotlib figure and pause execution.

>>> mapdl.aplot(vtk=False)
>>> mapdl.lplot(vtk=False)
>>> mapdl.kplot(vtk=False)

Area Plot from MAPDL displayed using Matplotlib

For more information on plotting functions, see Plotting.

Plotting keyword options

When vtk=True, which is the default, all MAPDL plotting methods allow you to enter in additional keyword arguments to better control the plot. For example, you can automatically generate a screenshot of an area plot or element plot with this code:

>>> mapdl.aplot(savefig="aplot.png")
>>> mapdl.eplot(savefig="eplot.png")

You can also control the camera position with cpos when you want to view from a standard viewing direction. This code shows how to view the XY plane with cpos='xy'.

>>> mapdl.eplot(cpos="xy")

For all general plotting options, see the ansys.mapdl.core.plotting.visualizer.MapdlPlotter class.

Plotting boundary conditions

Warning

This feature is beta so its functionalities and stability are limited. See the documentation regarding the allowed boundary conditions and targets.

It is possible to plot the boundary conditions applied on the model by specifying plot_bc=True in plotting functions. For example, this code specifies plot_bc=True for the Mapdl.nplot() method:

>>> mapdl.nplot(
...     plot_bc=True, plot_labels=True, savefig=f"bc_plot.png", bc_labels="mechanical"
... )

Mechanical boundary conditions Forces (arrows) and displacements (cones)

Note

Because boundary conditions can only target nodes, you can only use plot_bc as an argument in the Mapdl.nplot() method.

Boundary conditions demonstration