FVCOM-Grid-Generation/basic_mesh_example.py at main · SharknadoBear/FVCOM-Grid-Generation · GitHub

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import gmsh
import sys

# Initialize Gmsh
gmsh.initialize()

# Create a new model
gmsh.model.add("simple_mesh")

# Add a rectangle (2D geometry)
# lc = characteristic length (controls mesh size)
lc = 0.1
gmsh.model.geo.addPoint(0, 0, 0, lc, 1)
gmsh.model.geo.addPoint(1, 0, 0, lc, 2)
gmsh.model.geo.addPoint(1, 1, 0, lc, 3)
gmsh.model.geo.addPoint(0, 1, 0, lc, 4)

# Add lines connecting the points
gmsh.model.geo.addLine(1, 2, 1)
gmsh.model.geo.addLine(2, 3, 2)
gmsh.model.geo.addLine(3, 4, 3)
gmsh.model.geo.addLine(4, 1, 4)

# Add a surface (closed loop)
gmsh.model.geo.addCurveLoop([1, 2, 3, 4], 1)
gmsh.model.geo.addPlaneSurface([1], 1)

# Synchronize geometry
gmsh.model.geo.synchronize()

# Generate 2D mesh
gmsh.model.mesh.generate(2)

# Save the mesh
gmsh.write("rectangle_mesh.msh")

# View it (optional - opens GUI)
gmsh.fltk.run()

# Finalize
gmsh.finalize()

print("Mesh generated: rectangle_mesh.msh")