Hot Reload

During cadwork plugin development, changes to imported Python modules only take effect after restarting cadwork. Hot Reload let you refresh all modules instantly, no restart needed.

Developed by Design-to-Production : https://www.designtoproduction.com/en/

Requirements

Developed and tested with cadwork 3d version 2025, build 390.

.hotreloadignore uses a built-in pattern matcher (Python standard library only; no pip packages).

Installation

Download the repository and drop the plugin folder HotReload in your cadwork APIx64 folder or create a symlink to the API.x64 folder.

Cadwork guide : https://docs.cadwork.com/projects/cwapi3dpython/en/latest/get_started/ (note, the path for version 2025 is now ...\cadwork\userprofil_2025\3d\API.x64)

Usage

After you've made changes in your own python plugin and before running them, run Hot Reload instead of restarting cadwork

1. Make sure you add the current directory to the system path at the top of your entry point (main python file):

   import sys, os
   sys.path.insert(0, os.path.dirname(__file__))

2. subfolder modules are supported.
3. submodules outside APIx64 are supported (since 1ac2b14be360e45935e59092277c72e1758e7b5d).
4. Symlinked modules are supported.

.hotreloadignore (optional)

Each plugin folder under API.x64 may contain a .hotreloadignore file at its root (next to plugin_info.xml). Paths are matched relative to that plugin folder (use / in patterns even on Windows). Module files that match any rule are not unloaded.

This repository’s HotReload folder ships .hotreloadignore with mod:hotreload_utils* so Hot Reload does not evict its own helper package from sys.modules every run (fewer edge cases; edit HotReload.py itself is still rare—restart cadwork if you change that entry script).

Supported pattern subset (similar to .gitignore, not a full clone):

Syntax	Meaning
Leading /	Match only from the plugin root (not deeper arbitrary prefixes).
Trailing /	Directory-only: that folder and everything inside it.
*	Any characters except / within one path segment.
?	One character except /.
**	Across / (including “no extra folders”).
**/	Optional directory prefix (typical use: **/name.py).
# …	Comment line.
Lines starting with !	Not supported (skipped with a warning).
mod: prefix	Module name glob (fnmatch, dotted names). Use for packages outside your plugin tree (e.g. site-packages). Patterns from all .hotreloadignore files under API.x64 are merged.

Example API.x64/MyPlugin/.hotreloadignore:

# third-party tree — keep imported modules as-is
vendor/

# only at plugin root
/generated_constants.py

# any depth under this plugin
**/legacy_stable.py

# keep NumPy / PyClipper loaded (paths are outside this folder — use mod:)
mod:numpy*
mod:pyclipr*

Limitations

• Hot Reload unloads selected modules from sys.modules; updated code is imported on the next plugin run.
• If different projects load modules with the same name, one import path can still shadow another.
• In some host-runtime edge cases, long-lived references to old objects may remain; a full cadwork restart is then required.

License

MIT License — see LICENSE for details.