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Import FEM Mesh

Volvicon reads finite element meshes from solver files and loads them as volume mesh objects. The nodes and elements are imported and—where the file provides them—node sets, element sets, surfaces, materials, and parts come in too, so a mesh saved from one solver can be inspected, edited, visualized, and exported again to another solver's format.

There is no separate tool or button for solver files: they are imported through the standard volume mesh import, exactly like a VTK mesh. Each import creates a new volume mesh object, and the format is detected automatically from the file's extension and contents.

How to Import​

  • Menu: File ▸ Import ▸ Volume Mesh Models, then select the file. See Import.
  • Drag and drop: drop a supported file onto the 3D view.
  • Scripting: volume_mesh_operations.import_volume_mesh_from_disk(path).

Supported Import Formats​

FormatExtensionDescription
VTK.vtu, .vtkVTK unstructured grids
Abaqus / CalculiX.inpAbaqus and CalculiX input files
Nastran.bdf, .nasMSC, NX, and Simcenter Nastran bulk data files
LS-DYNA.k, .dyn, .keyLS-DYNA keyword input files
ANSYS.cdbANSYS Mechanical APDL archive files
Gmsh.mshGmsh mesh files (versions 2.2 and 4.1)
Fluent.mshANSYS Fluent mesh files
OpenFOAM.foamOpenFOAM case (.foam marker file or the case directory)

What Gets Imported​

The mesh geometry—nodes and solid/shell elements—is always imported. The following are imported when the file stores them:

  • Materials – material names and properties.
  • Node sets and element sets – named collections of nodes and elements.
  • Surfaces – boundary face collections.
  • Parts – element groups with their assigned material and section.

Element handling​

Volume mesh tools work on solid and shell cells, so the import keeps those and normalizes the rest:

  • Solid and shell cells – tetrahedra, hexahedra, wedges, pyramids, triangles, and quadrilaterals are imported as the volume mesh, including non-tetrahedral solids.
  • Higher-order (quadratic) elements are imported as their linear equivalents, keeping the corner nodes, so they display and measure consistently with the rest of the volume mesh.
  • 1D elements – beams, trusses, rods, and springs are structural connectors rather than volume cells, so they are not imported as mesh elements.
  • Solver helper entities – contact, target, and surface-effect elements are skipped so they do not appear as stray, degenerate cells.
  • Unused nodes left after the above are removed so node counts reflect the imported mesh.

Notes​

  • Round trips – a mesh exported from Volvicon to any of these formats can be imported back; the nodes and elements are preserved.
  • CFD formats – Fluent and OpenFOAM describe the mesh through its faces, so Volvicon rebuilds each solid cell from its bounding faces on import.
  • OpenFOAM input – point the import at the .foam case marker file or at the case directory itself (a folder containing the mesh files, a polyMesh folder, or a constant/polyMesh folder).
  • .msh detection – Gmsh and Fluent both use the .msh extension; Volvicon tells them apart by inspecting the file contents, so either imports correctly without choosing a format.

Scripting Example​

import ScriptingApi as api

app = api.Application()
volume_mesh_operations = app.get_volume_mesh_operations()

# Import a solver file. This creates a new volume mesh object.
mesh_name = volume_mesh_operations.import_volume_mesh_from_disk(r"C:\data\model.inp")
if mesh_name:
    fem_operations = volume_mesh_operations.get_fem_operations()
    stats = fem_operations.get_model_statistics(mesh_name)
    print(f"Imported {stats.node_count} nodes and {stats.element_count} elements")
    print(f"  Materials: {stats.material_count}, Parts: {stats.part_count}")
    print(f"  Node sets: {stats.node_set_count}, Element sets: {stats.element_set_count}")
    print(f"  Surfaces: {stats.surface_count}")

The same call imports every supported format—.inp, .bdf, .nas, .k, .cdb, .msh, and so on—and detects the format automatically. Pass a list to import_volume_meshes_from_disk(...) to import several files at once.