First check

• I added a very descriptive title here.
• I used the GitHub search to find a similar question and didn't find it.
• I searched the PyVista documentation, with the integrated search.
• I already searched in Google "How to X in PyVista" and didn't find any information.
• I already read and followed all the tutorial in the docs and didn't find an answer.
• I will NOT make duplicate discussions or issues in the future.

Commit to Help

• I commit to help with one of those options.

Sample Code What is the problem, question, or error?

Write a short description telling me what you are doing, what you expect to happen, and what is currently happening.

import pyvista as pv
import numpy as np

cube_points = np.array([
    [0.0, 0.0, 0.0],  # 0
    [1.0, 0.0, 0.0],  # 1
    [1.0, 1.0, 0.0],  # 2
    [0.0, 1.0, 0.0],  # 3
    [0.0, 0.0, 1.0],  # 4
    [1.0, 0.0, 1.0],  # 5
    [1.0, 1.0, 1.0],  # 6
    [0.0, 1.0, 1.0],  # 7
])

cube_cells = np.hstack([[8, 0, 1, 2, 3, 4, 5, 6, 7]])
cube = pv.UnstructuredGrid(cube_cells, np.array([pv.CellType.HEXAHEDRON]), cube_points)

plane_points = np.array([
    [0.25, 0.25, 1.0+1e-9],  # 0
    [0.75, 0.25, 1.0+1e-9],  # 1
    [0.75, 0.75, 1.0+1e-9],  # 2
    [0.25, 0.75, 1.0+1e-9],  # 3
])

plane_cells = np.hstack([[4, 0, 1, 2, 3]])
plane = pv.UnstructuredGrid(plane_cells, np.array([pv.CellType.QUAD]), plane_points)

plotter = pv.Plotter()
plotter.add_mesh(cube, color="lightblue", opacity=0.9, show_edges=True)
plotter.add_mesh(plane, color="red", opacity=1.0, show_edges=True)
plotter.show()

Description

I am making a FEM library where I want to plot both geometries consisting of tetrahedra and surfaces on them.
I regularly have to plot surfaces on top of geometries such as copper traces on a volume (dielectric). Of course this causes a certain level of z-fighting.

I have information by which I could (in theory) decide which geometry takes priority in cases of z-fighting but I don't know how to use that to actually prevent it. My current solution just lifts up those geometries by 1um (absolute coordinates) but that only works when zoomed in close enough.

I have looked through the documentation, google, anything but couldn't find a mention of Z-fighting/Stitching/Planefighting anywhere.

What is the best approach to deal with this? I've tried messing with different settings for enable_depth_peeling. Turning it off works but then the opacity of the volumes doesn't work anymore (maybe change to some volumetric opacity?)

System Information

--------------------------------------------------------------------------------
  Date: Tue Aug 26 11:34:44 2025 CEST

                OS : Darwin (macOS 15.5)
            CPU(s) : 14
           Machine : arm64
      Architecture : 64bit
       Environment : Python
        GPU Vendor : Apple
      GPU Renderer : Apple M4 Pro
       GPU Version : 4.1 Metal - 89.4
     Render Window : vtkCocoaRenderWindow
  MathText Support : True

  Python 3.10.18 (main, Jun 12 2025, 12:22:33) [Clang 20.1.4 ]

           pyvista : 0.45.2
               vtk : 9.4.2
             numpy : 2.2.6
        matplotlib : 3.10.3
            scooby : 0.10.1
             pooch : 1.8.2
            pillow : 11.2.1
             scipy : 1.15.3
--------------------------------------------------------------------------------

Screenshots