space_view3d_move_origin.py

bl_info = {
    'name': 'Move origin to selected',
    'author': 'Dealga McArdle (zeffii)',
    'version': (0, 0, 1),
    'blender': (2, 6, 7),
    'location': '3d view > space bar > Origin Move to Selected',
    'description': 'in edit mode, sets object origin to the median of selected verts/edges/faces',
    'wiki_url': '',
    'tracker_url': '',
    'category': '3D View'}

import bpy
import mathutils

class MoveOrigin(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "object.origin_to_selected"
    bl_label = "Origin Move To Selected"
    bl_options = {'REGISTER', 'UNDO'}

    @classmethod
    def poll(cls, context):
        obj = context.active_object
        return obj is not None and obj.mode == 'EDIT'

    def execute(self, context):
        from mathutils import Vector

        bpy.ops.object.mode_set(mode = 'OBJECT')
        obj = context.active_object

        selected_verts = [v.co for v in obj.data.vertices if v.select]

        for v in selected_verts:
            median += v
        median /= len(selected_verts)
                
        obj.data.transform(mathutils.Matrix.Translation(-median))
        obj.location += median
        bpy.ops.object.mode_set(mode = 'EDIT')
        return {'FINISHED'}


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


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


if __name__ == "__main__":
    register()