Import & Export

File formats, interoperability with LBNL THERM, and built-in examples.

Native Format (.therm.json)

ThermX uses a JSON-based native format with the .therm.json extension. It stores the complete project state: regions with vertices and materials, boundary conditions with edge references, layers, groups, results display settings, and sheet layouts.

• File → Save — save the current project
• File → Open — load a previously saved project

THMX (LBNL THERM Format)

ThermX provides full read/write support for the THMX file format used by LBNL THERM. This allows you to open existing THERM models and save files compatible with THERM.

Import

Go to File → Import THMX to open a .thmx file. ThermX parses:

• Materials — name, conductivity, emissivity (front/back), color (0xRRGGBB → #RRGGBB), category (solid/gas/insulation/glazing)
• Boundary Conditions — type (convective/fixed temp/adiabatic), film coefficient, temperature, radiation parameters
• Polygons — vertices, material assignment, polygon IDs
• BC Assignments — BCPolygon elements with PolygonID-based region lookup
• Mesh Control — mesh level settings
• Header — title, units, creator info

Export

Go to File → Export THMX to save. ThermX writes all spec attributes:

• Full header (Title, CreatedBy, Units, MeshControl)
• Materials with all 8 Property sub-elements for solids; gas materials with CavityModel
• BCs with full radiation/flag parameters
• Polygons with NSides, Type, units, vertices
• BCPolygon with PolygonID, EnclosureID, UFactorTag, Emissivity
• XML escaping for special characters in names

DXF

Import

File → Import DXF reads AutoCAD DXF files and converts geometry entities (lines, polylines, closed polygons) into ThermX regions. Powered by the dxf-parser library.

Export

File → Export DXF produces an ASCII DXF file with organized layers:

• GEOMETRY — region outlines
• BOUNDARY_CONDITIONS — BC edge assignments
• ISOTHERMS — isotherm contour lines (if results available)
• LABELS — material names and annotations

DWG Import

File → Import DWG converts AutoCAD DWG files to DXF using dwg2dxf from LibreDWG, then parses the resulting DXF.

• Ubuntu/Debian: sudo apt install libredwg-tools
• macOS: brew install libredwg
• Windows: download from the LibreDWG releases page

PNG Export

File → Export PNG captures the current canvas view as a PNG screenshot, including geometry, materials, mesh, temperature map, isotherms, and legends — whatever is currently visible.

PDF Export

PDF export is available from the Sheets tab. See Sheet Views & PDF for details. PDFs include vector text and lines with high-DPI viewport renders.

Import as Group

File → Import Group lets you load another .therm.json file and insert its regions as a new group within the current project. Useful for assembling complex models from reusable components (e.g., importing a spacer detail into a window frame model).

Built-in Examples

ThermX ships with example files accessible from File → Open Example:

File Format Summary