The aim of this is to avoid having to set the selection each time before running an operator from python. At the moment this is set as a python dictionary with string keys and rna values... eg. C = {} C["active_object"] = bpy.data.objects['SomeOb'] bpy.ops.object.game_property_new(C) # ofcourse this works too.. bpy.ops.object.game_property_new({"active_object":ob}) # or... C = {"main":bpy.data, "scene":bpy.data.scenes[0], "active_object":bpy.data.objects['SomeOb'], "selected_editable_objects":list(bpy.data.objects)} bpy.ops.object.location_apply(C)