Implicit2TetMesh.jl

Implicit2TetMesh is an experimental Julia package for generating high-quality tetrahedral meshes from implicit geometries defined by Signed Distance Functions (SDFs), inspired by isosurface stuffing algorithm. Implementation details are provided in the documentation below. For practical usage examples, see test/Examples/.

Features

• Robust Meshing: High-quality tetrahedral mesh generation from implicit geometries using A15 (body-centered cubic) and Schlafli (orthoscheme) discretizations
• Isosurface Refinement: Advanced boundary processing with experimental NZZZ case handling for thin features relative to characteristic element size
• Volume Correction: Precise volume preservation using automatic surface node adjustment
• Geometric Constraints: Bounded plane definitions for selective node alignment
• Mesh Operations: Slicing, isolated component removal, inverted element fixing, and VTU export with mesh quality metrics

Installation

Requirements: Julia LTS (1.10.10)

# From Julia REPL, press ] to enter package mode
pkg> add https://github.com/jezekon/Implicit2TetMesh.jl

or

git clone https://github.com/jezekon/Implicit2TetMesh.jl

Main Function

Generate tetrahedral meshes from SDF data:

generate_tetrahedral_mesh(grid_file, sdf_file, output_prefix; options=MeshGenerationOptions())

Parameters:

• grid_file::String: Path to the JLD2 file containing the grid data
• sdf_file::String: Path to the JLD2 file containing the SDF values
• output_prefix::String: Prefix for output files (default: "output")
• options::MeshGenerationOptions: Configuration options (optional)

Return Value:

• mesh::BlockMesh: The generated tetrahedral mesh
• Output files: .vtu mesh visualization files for Paraview

MeshGenerationOptions

Configure the mesh generation process with the following options:

MeshGenerationOptions(;
    scheme::String = "A15",                           # Discretization scheme: "A15" or "Schlafli"
    warp_param::Float64 = 0.3,                        # Warping intensity for plane alignment (0.0 = disabled)
    plane_definitions::Union{Vector{PlaneDefinition}, Nothing} = nothing,  # Cutting planes for BC application
    quality_export::Bool = false,                     # Export detailed quality metrics
    correct_volume::Bool = false,                     # Apply volume correction algorithm
    experimental_nzzz::Bool = false                   # Enable experimental NZZZ case warping
)

Option Details

• scheme:
  • "A15": Body-centered cubic lattice discretization (recommended for most cases)
  • "Schlafli": Orthoscheme discretization (better for axis-aligned features)
• warp_param: Controls how strongly nodes are attracted to cutting planes (0.0-1.0 range recommended)
• plane_definitions: Vector of PlaneDefinition objects for boundary plane constraints
• quality_export: When true, exports additional quality metrics (Jacobian determinants, dihedral angles, volume ratios)
• correct_volume: Enables iterative volume correction to match reference SDF volume (may increase processing time)
• experimental_nzzz: Enables experimental warping for NZZZ cases (one node outside, three on surface). Use with caution.

Example Usage

using Implicit2TetMesh

# Basic usage with default options
mesh = generate_tetrahedral_mesh(
    "path/to/grid_data.jld2",
    "path/to/sdf_data.jld2",
    "beam"
)

Advanced Usage Examples

For complete examples with detailed documentation, see test/Examples/:

# Run beam example
julia --project=. test/Examples/beam.jl

julia --project=. test/Examples/gripper.jl

---

TODO List

• Improve NZZZ case handling based on dihedral angles
• Add support for NNZZ cases (two nodes outside, two on surface)
• Performance optimizations for large meshes

Acknowledgments

This package is an experimental tool. Please validate results carefully.