Expand geometry handling in `generateMeshFromGeometry()` function

[nikoscham]

This issue has been added to the FEAScript roadmap for the upcoming 0.2.0 release (https://github.com/orgs/FEAScript/discussions/17). Currently, the generateMeshFromGeometry() function supports only rectangular domains. We aim to extend this functionality to support additional 2D geometries (trapezoid-shaped & ring (annulus)-shaped), enabling users to more easily create meshes for diverse simulation domains. The relevant function is located in meshGenerationScript.js (https://github.com/FEAScript/FEAScript-core/blob/main/src/mesh/meshGenerationScript.js).

Tasks

• Implement support for trapezoid-shaped 2D domains
• Implement support for 2D ring (annulus)-shaped domains
• Add support for expansion ratio in mesh generation (e.g., graded mesh density along one direction)

[Harshalyadav]

Hi,
I am interested in working on this issue and will start working on it between 30 Sep to 2nd October.

[nikoscham]

Hi, I am interested in working on this issue and will start working on it between 30 Sep to 2nd October.

Welcome to the FEAScript community Harshal (@Harshalyadav)! Thank you for your interest in contributing to the project.
Adding support for additional 2D geometries will be a very valuable feature for the library.
I’ll get back to you soon with some extra instructions regarding the task!

Best regards and please also consider ⭐️ the library!
Nikos

[nikoscham]

Hi @Harshalyadav! Here are some guidelines to help you tackle this task.

First, examine the existing code in src/mesh/meshGenerationScript.js to understand how rectangular domains are handled. The current implementation:

• Creates a structured grid of nodes
• Generates elements by connecting these nodes
• Assigns proper element connectivity

Implementation Plan

1. Modify the Configuration Structure
Extend setMeshConfig() to accept the new geometries as shown in the provided examples:

// Rectangle (existing)
model.setMeshConfig({
  meshDimension: "2D",
  elementOrder: "quadratic",
  numElementsX: 8,
  numElementsY: 4,
  geometryShape: "rectangle",  // Add this parameter
  maxX: 4,
  maxY: 2,
});

// Trapezoid (new)
model.setMeshConfig({
  meshDimension: "2D",
  elementOrder: "quadratic",
  numElementsX: 8,
  numElementsY: 4,
  geometryShape: "trapezoid",
  shortBaseX: 1, // length of the shorter parallel side
  longBaseX: 3, // length of the longer parallel side
  maxY: 2, // height
});

// Annulus (new)
model.setMeshConfig({
  meshDimension: "2D",
  elementOrder: "quadratic",
  numElementsR: 8, // radial elements
  numElementsTheta: 16, // angular elements
  geometryShape: "annulus",
  minR: 1, // radius of the inner boundary
  maxR: 2, // radius of the outer boundary
});

2. Implement Trapezoid Mesh Generation

• For each row of nodes (y-coordinate), calculate the corresponding width
• Use linear interpolation between shortBaseX and longBaseX based on y position
• Position nodes at equidistant points along each row

3. Implement Annulus (Ring) Mesh Generation

• Use polar coordinates (r, θ) for node positioning
• Convert to Cartesian coordinates (x, y) for storage

4. Add Support for Expansion Ratio
Implement a graded mesh density by adding an expansion ratio option:

// For rectangle or trapezoid
model.setMeshConfig({
  // Other parameters...
  expansionRatioX: 1.2, // values > 1 make elements larger in positive X direction
  expansionRatioY: 0.8, // values < 1 make elements smaller in positive Y direction
});

// For annulus (expansion is radial)
model.setMeshConfig({
  // Other parameters...
  expansionRatioR: 1.2 // For annulus, this controls radial expansion
});

Please do what you can—if you cannot complete everything 100%, that’s totally fine! Just push as far as you can, and we can continue or review together.

Thanks a lot for your work on this!