AlignGeometry.py

bl_info = {
    "name": "Align Geometry",
    "author": "Dealga McArdle",
    "version": (0, 1),
    "blender": (2, 7, 6),
    "location": "",
    "description": "align mid, neg, pos",
    "warning": "",
    "wiki_url": "",
    "tracker_url": "",
    "category": "3D View"
}

import bpy
import bmesh


def align(mode, axis):

    obj = bpy.context.edit_object
    me = obj.data
    bm = bmesh.from_edit_mesh(me)

    if mode == 'm':
        a = bm.faces.active.calc_center_median()
        amount = getattr(a, axis)
        for f in bm.faces:
            if f == bm.faces.active:
                continue

            if f.select:
                p = f.calc_center_median()
                pamount = getattr(p, axis)
                diff = amount - pamount

                for v in f.verts:
                    co = v.co
                    pos = getattr(co, axis)
                    setattr(co, axis, pos + diff)

    bmesh.update_edit_mesh(me, True)


class MeshAlignVerts(bpy.types.Operator):
    """ tooltip"""
    bl_label = "Align Geometry"
    bl_idname = "mesh.zs_align_geometry"

    def execute(self, context):
        scn = context.scene
        align(mode=scn.zs_selected_mode, axis=scn.zs_selected_axis)
        return {'FINISHED'}


class ZSAlignPanel(bpy.types.Panel):
    """ tooltip"""
    bl_label = "zs align panel"
    bl_idname = "SCENE_PT_layout_align"
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'TOOLS'

    def draw(self, context):
        layout = self.layout
        scn = context.scene

        col = layout.column()
        col.prop(scn, "zs_selected_mode", expand=True)
        col.prop(scn, "zs_selected_axis", expand=True)

        row = layout.row(align=True)
        row.operator('mesh.zs_align_geometry', text='Align')


def register():
    S = bpy.types.Scene
    S.zs_selected_mode = bpy.props.EnumProperty(
        items=[(n, n, '', i) for i, n in enumerate('m+-')],
        description="offers mode of alignment",
        default="m"
    )
    S.zs_selected_axis = bpy.props.EnumProperty(
        items=[(n, n, '', i) for i, n in enumerate('xyz')],
        description="offers axis selection",
        default="z"
    )
    bpy.utils.register_module(__name__)


def unregister():
    bpy.utils.unregister_class(__name__)
    S = bpy.types.Scene
    del S.zs_selected_mode
    del S.zs_selected_axis


if __name__ == "__main__":
    register()