Create Layer Mask from...

GIMP 2.8 Python Plug-in.
This plugin allows you to create layer mask from another layer mask.
Or create layer mask from grayscale copy of layer.

In addition, the main feature of this plug-in - is an option that allows you to change the interaction between two masks (Replace, Subtract...):

Installation Instructions:
1. Extract "create-layer-mask-from.py" from zip archive to the ".../.gimp-2.x/plug-ins" directory.
2. If you're on a UNIX system, make sure "create-layer-mask-from.py" is executable.
3. Once you have saved the file in your plug-ins folder, if you are already running GIMP, close and reopen it.
4. If you have done this correctly, the scripts will appear in the menu under: "/Layer/Mask/Create Layer Mask from..." and "/Create Layer Mask from...".

This plug-in requires Python!
If you have the "Filters > Python-Fu > Console" menu item you are all set. If not, install Python support for GIMP.

This script tested with GIMP 2.8.

Download:
Download from my deviantart page:
slybug.deviantart.com

Version History:
v1.0 (30.08.2012)
- Initial release.

My other plugins:
Scale Layer to Image Size
Layer via Copy/Cut