execute_code_async
Run heavy Python computations in FreeCAD in the background, preventing UI freezes while avoiding GUI and document modifications.
Instructions
Execute Python code in FreeCAD without waiting for completion.
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:
Fetch shapes into local variables first (via execute_code on the GUI thread).
Store intermediate results in a module-level Python variable (not in the FreeCAD document) so execute_code can read them later.
Run the heavy computation via execute_code_async.
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
| Name | Required | Description | Default |
|---|---|---|---|
| code | Yes |