space_view3d_panel_measure.py

            elif len(context.selected_objects) == 2:
                # 2 objects selected.
                # We measure the distance between the 2 selected objects.

                obj1, obj2 = context.selected_objects

                box = layout.box()
                row = box.row()
                row.prop(sce, "measure_panel_dist")

                row = box.row()
                row.label(text="", icon='OBJECT_DATA')
                row.prop(obj1, "name", text="")

                row.label(text="", icon='ARROW_LEFTRIGHT')

                row.label(text="", icon='OBJECT_DATA')
                row.prop(obj2, "name", text="")

                row = layout.row()
                row.prop(sce, "measure_panel_calc_area",
                    text="Surface area:")

                if (sce.measure_panel_calc_area):
                    # Display surface area of the objects.
                    if (sce.measure_panel_area1 >= 0
                    or sce.measure_panel_area2 >= 0):
                        if (sce.measure_panel_area1 >= 0):
                            box = layout.box()
                            row = box.row()
                            row.label(text=obj1.name, icon='OBJECT_DATA')

                            row = box.row()
                            row.label(text="Area")
                            row.prop(sce, "measure_panel_area1")

                            row = box.row()
                            row.label(text="Normal")
                            row = box.row()
                            row.prop(sce, "measure_panel_normal1")

                        if (sce.measure_panel_area2 >= 0):
                            box = layout.box()
                            row = box.row()
                            row.label(text=obj2.name, icon='OBJECT_DATA')

                            row = box.row()
                            row.label(text="Area")
                            row.prop(sce, "measure_panel_area2")

                            row = box.row()
                            row.label(text="Normal")
                            row = box.row()
                            row.prop(sce, "measure_panel_normal2")

                        row = layout.row()
                        row.prop(sce,
                            "measure_panel_transform",
                            expand=True)

            elif (obj):
                # One object selected.
                # We measure the distance from the object to the 3D cursor.

                box = layout.box()
                row = box.row()
                row.prop(sce, "measure_panel_dist")

                row = box.row()
                row.label(text="", icon='CURSOR')

                row.label(text="", icon='ARROW_LEFTRIGHT')

                row.label(text="", icon='OBJECT_DATA')
                row.prop(obj, "name", text="")

                row = layout.row()
                row.prop(sce, "measure_panel_calc_area",
                    text="Surface area:")

                if (sce.measure_panel_calc_area):
                    # Display surface area of the object.

                    if (sce.measure_panel_area1 >= 0):
                        box = layout.box()
                        row = box.row()
                        row.label(text=obj.name, icon='OBJECT_DATA')

                        row = box.row()
                        row.label(text="Area")
                        row.prop(sce, "measure_panel_area1")

                        row = box.row()
                        row.label(text="Normal")
                        row = box.row()
                        row.prop(sce, "measure_panel_normal1")

                        row = layout.row()
                        row.prop(sce,
                            "measure_panel_transform",
                            expand=True)

            elif not context.selected_objects:
                # Nothing selected.
                # We measure the distance from the origin to the 3D cursor.

                box = layout.box()
                row = box.row()
                row.prop(sce, "measure_panel_dist")

                row = box.row()
                row.label(text="", icon='CURSOR')
                row.label(text="", icon='ARROW_LEFTRIGHT')
                row.label(text="Origin [0,0,0]")

            else:
                row = layout.row()
                row.label(text="Selection not supported.",
                    icon='INFO')


def register():
    bpy.utils.register_module(__name__)

    # Define a temporary attribute for the distance value
    bpy.types.Scene.measure_panel_dist = bpy.props.FloatProperty(
        name="Distance",
        precision=PRECISION,
        unit="LENGTH")
    bpy.types.Scene.measure_panel_area1 = bpy.props.FloatProperty(
        precision=PRECISION,
        unit="AREA")
    bpy.types.Scene.measure_panel_area2 = bpy.props.FloatProperty(
        precision=PRECISION,
        unit="AREA")
    bpy.types.Scene.measure_panel_normal1 = bpy.props.FloatVectorProperty(
        precision=PRECISION,
        subtype="XYZ")
    bpy.types.Scene.measure_panel_normal2 = bpy.props.FloatVectorProperty(
        precision=PRECISION,
        subtype="XYZ")

    TRANSFORM = [
        ("measure_global", "Global",
            "Calculate values in global space."),
        ("measure_local", "Local",
            "Calculate values inside the local object space.")]

    # Define dropdown for the global/local setting
    bpy.types.Scene.measure_panel_transform = bpy.props.EnumProperty(
        name="Space",
        description="Choose in which space you want to measure.",
        items=TRANSFORM,
        default='measure_global')

    # Define property for the draw setting.
    bpy.types.Scene.measure_panel_draw = bpy.props.BoolProperty(
        description="Draw distances in 3D View",
        default=1)

    # Define property for the calc-area setting.
    # @todo prevent double calculations for each refresh automatically?
    bpy.types.Scene.measure_panel_calc_area = bpy.props.BoolProperty(
        description="Calculate mesh surface area (heavy CPU" \
            " usage on bigger meshes)",
        default=0)

    pass


def unregister():
    bpy.utils.unregister_module(__name__)

    pass

if __name__ == "__main__":
    register()