execute_code_async
Run Python code in FreeCAD asynchronously for long, CPU-bound computations that avoid GUI and document interaction.
Instructions
Execute Python code in FreeCAD without waiting for completion.
This is an unverified escape hatch: prefer the typed tools (pad, pocket,
place, measure, probe_material_at, fillet, chamfer, linear_pattern,
polar_pattern, create_sketch/add_rectangle/add_circle/add_polygon,
instantiate_family) for normal geometry work, since they check what
actually happened instead of only reporting whether the code raised.
Code containing process-level imports (os/subprocess), eval/exec/open/
__import__, or Sketcher calls known to hang FreeCAD's solver (.solve(),
deleteAllGeometry(), movePoint() on an already-constrained sketch) is
rejected before it runs.
Use this ONLY for long-running background computations that do NOT touch the
FreeCAD GUI or mutate the FreeCAD document tree directly.
This tool runs the submitted code in a background thread and returns
immediately. Because it does not run on FreeCAD's main GUI thread, the code
must NOT call FreeCADGui APIs, manipulate the active view or selection, create
or edit document objects, change object properties, call doc.recompute(), or
save documents.
For code that touches FreeCAD documents, document objects, FreeCADGui, the
active view, selection, recompute, or save operations, use execute_code instead.
execute_code runs on the FreeCAD GUI thread and is the safe default for normal
FreeCAD automation.
Use execute_code_async only for background-safe work such as long-running
pure OCCT geometry calculations (e.g. fuse/cut/loft on already-fetched shapes)
or other CPU-bound computations that do not interact with the document or GUI.
Typical usage pattern:
1. Fetch shapes into local variables first (via execute_code on the GUI thread).
2. Store intermediate results in a module-level Python variable (not in the
FreeCAD document) so execute_code can read them later.
3. Run the heavy computation via execute_code_async.
4. After the expected computation time has elapsed, apply results to the
document via execute_code (which runs on the GUI thread).
Args:
code: Background-safe Python code to execute.
Returns:
A message confirming that background execution has started.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| code | Yes |
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |