Files, import and export

Projects

A project is a .magfem file (JSON) with the drawing, variables, materials, mesh, physics and views. Results are recomputed on opening.

  • New, Open, Save and Save as are on the top bar.

  • In Chrome and Edge, Save writes back to the same file, like an installed program; Save as picks another one. In Firefox and Safari, saving triggers a download.

  • Nothing leaves your machine: there is no server, account or cloud.

Draft and automatic copies

The open project is kept in the browser (draft) on every change: closing the tab without saving does not lose the work. Also, after every minute of editing the previous version becomes an automatic copy (up to 10). If the project opens empty, a banner offers to recover the latest copy; the full list is under Automatic copies. Recovering can be undone.

Warning

The draft lives in the browser storage. Clearing the site data deletes the draft and the copies. Save important projects to a file.

Import

Import accepts:

Format

What comes in

DXF

lines, arcs, circles and polylines; coincident points are merged so regions close

SVG

paths (with arcs) converted to lines and arcs

FEMM (.fem)

geometry, materials, boundaries, circuits and block labels. Unlabeled regions stay out of the mesh, and edges without a property stay Neumann, as in FEMM

FEMM materials are also available under Materials › Import from FEMM… (reads matlib.dat) and in the material list search.

Export

The Export button (top bar) exports what is in the active tab:

Active tab

Formats

Drawing

SVG (vector, in mm), DXF (LibreCAD, FreeCAD…), PNG, JPG

Field view

PNG, JPG

Plot over line, B-H curve

SVG, PNG, JPG, CSV

Circuit table

CSV

Also:

What

Where

Animation (WebM)

view bar, in transient and AC

Time plot (CSV, MAT, SVG, PNG)

buttons below the plot, in the table tab

Model as code

</> button next to Model: console script that rebuilds the project

The exported script rebuilds the model exactly, with the same ids. It is the basis for automation.