Blender addon for cutting your geometry. Grab it from here. Compared to other blender Carving addons, this addon works in edit mode.
Located in left Tool Shelf-> Tools-> Trim View.
- Knife trim – cut geometry with knife tool. If this tool is not behaving as it should, try switching ‘Trim Type’ parameter from ‘dissolve’ to ‘KDTree search’ (slower) or vice versa.
- Trim by selection -(based on bisect tool) cut mesh in plane based on selected geometr. To define plane – select 2 or more vertices, then use this tool. After that you can offset the cut plane by pressing F6 and changing depth parameter.
This addon may not work on complex geometry as expected. This is partially due to old blender carve (boolean) module. It was being worked by blender devs, but for now it is disabled. Maybe it will be enabled again in blender 2.8?