How Can I Select All Inner Faces of a Current Selection of Faces?

Question

I want to go from this:

To This:

Ideally, in one single operation. There appears to be a straightforward way to do this if the selection happens to be Edges. From the Select Menu, I can choose Select > Select Loops > Select Loop Inner Region. However, if the selection is originally Faces, the feature breaks, removing some of the original face selections, while adding no new ones. I realize that I could make my initial selection in Edges, then choose Select Loop Inner Region, and after it creates the selection, simply use the 3 key to switch back to Faces, and that would give me the result I am after. But this means extra steps that shouldn't be necessary. It seems to me that since there is something called an edge loop, as well as something called a face loop, and also, since this Select Menu doesn't specify edges nor faces in its wording, that the feature should work with either edges or faces. But it doesn't. So what does? What works to select all inner faces of a selection of faces?

Answer 1

It's not one operation, but it is quick, and Blenderish, (no faffing with menus, no operations on things you can't see)..

• H hide the selected boundary faces...
• Hover over the interior with L to pick them all up...
• Alt H to bring the boundary back.

... thanks to @Arda for noting an important and often-missed feature of H and Alt H:

To include/exclude the border in the final selection, check/uncheck "Select" in the "Reveal Hidden" options that come up after you press Alt H

Answer 2

Building up on the idea from @Robin Betts:

bl_info = {
    "name": "Select inside face loop",
    "blender": (4, 0, 0),
    "category": "Mesh",
}

import bpy

class MESH_OT_select_inside_face_loop(bpy.types.Operator):
    bl_idname = "mesh.select_inside_face_loop"
    bl_label = "Select inside face loop"
    bl_options = {'REGISTER', 'UNDO'}

    event: bpy.types.Event
    location: tuple[int,int]


    def execute(self, context):
        ops = bpy.ops
        mesh = ops.mesh

        mesh.hide()
        ops.view3d.select(location = self.location)
        mesh.select_linked()
        mesh.reveal()
        return {'FINISHED'}


    def invoke(self, context, event):
        self.event = event
        self.location = (event.mouse_region_x, event.mouse_region_y)
        return self.execute(context)


def register():
    bpy.utils.register_class(MESH_OT_select_inside_face_loop)


def unregister():
    bpy.utils.unregister_class(MESH_OT_select_inside_face_loop)

if __name__ == "__main__":
    register()

Can be easily bound to a key/mouse shortcut and parametrized further as needed. Tested in Blender 4.0.x, I guess it should work for earlier and later versions as well.

Answer 3

Why not just Ctrl+Click then Ctrl+Shift+Click?

Or just directly Click one face at one corner and then Ctrl+Shift+Click the opposite corner.