JSBeam - Plane Frame and Truss Calculation Web Application

JBeam Compatibility: JSBeam uses the same model file format and algorithms as JBeam (Java-based desktop application) to ensure full compatibility and data interchange between platforms.

Copyright (C) 2025 Kai Gerd Schwebke

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.

Features

• Client-only web application for modern browsers
• No-build workflow using native ES modules with modular architecture
• Built with Preact and HTM (Hyperscript Tagged Markup)
• Modular codebase with 6 focused modules for maintainability and scalability
• Responsive design with dynamic SVG grid and viewport navigation
• Dark mode support with system preference detection
• Menu system with dropdown functionality (File, Mode, View, Help)
• Theme persistence using localStorage
• JBeam JSON format compatibility for cross-platform model sharing
• x-z coordinate system matching structural analysis conventions
• Viewport pan and zoom with extreme zoom range (1e-8 to 1e+8)
• Interactive node placement with real-time coordinate tracking
• Node properties editor with right-click access and complete property control
• JBeam-compatible visual symbols for constraints, forces, and moments
• Application modes for different interaction types
• Adaptive grid system that scales with zoom level

Current State

JSBeam has implemented comprehensive interactive modeling capabilities with a modular architecture:

• Modular codebase decomposed into 6 focused modules (reduced main.js from ~1000 to ~215 lines)
• Menu bar with File, Mode, View, and Help menus
• Content area with navigable grid visualization and node placement
• Status bar with real-time coordinate tracking and zoom level display
• Light/dark theme switching with system preference detection
• Responsive layout that adapts to screen size
• Interactive node entry with click-to-place functionality
• Application modes (select, addNode) with extensible architecture
• Viewport navigation with middle mouse pan and Ctrl+wheel zoom
• Extreme zoom capabilities (1e-8 to 1e+8) for dimensionless analysis
• Node properties editor with right-click access for complete property control
• JBeam-compatible visual representation with constraint symbols, force vectors, and moment indicators
• Structural modeling features including position, constraints, loads, and labels
• Adaptive grid system that automatically adjusts spacing
• Real-time coordinate tracking in x-z coordinate system
• JBeam-compatible model structure for structural analysis
• URL-based model management for persistence and sharing
• Multi-instance support for independent models in different browser tabs
• Keyboard shortcuts for mode switching (Ctrl+1, Ctrl+2)

Planned Features

The next development phase will focus on:

• Beam entry to connect nodes with structural elements
• Load application for forces, moments, and distributed loads
• Support definition for boundary conditions and constraints
• Structural analysis calculations using JBeam-compatible algorithms
• Results visualization with deformed shapes and force diagrams

Development

To run JSBeam locally:

1. Serve the static/ directory with any HTTP server
2. Or use the provided docker-run.sh script for containerized development
3. Open in a modern browser that supports ES modules and import maps

Documentation

• doc/ADR-001-dark-mode.md - Dark mode implementation architecture (implemented)
• doc/ADR-002-interactive-node-entry.md - Interactive node entry and JBeam compatibility (implemented)
• doc/ADR-003-viewport-pan-zoom.md - Viewport pan and zoom with extreme zoom capabilities (implemented)
• doc/ADR-004-node-properties-editor.md - Node properties editor and JBeam-compatible visual representation (implemented)
• doc/ADR-005-module-decomposition.md - Module decomposition for maintainability and scalability (implemented)
• doc/jbeam-model-schema.json - JBeam JSON schema for model validation