user: Give a detailed overview of Interface: syntax, arguments, return values, common patterns.

assistant: Each modifier’s interface shares the same basic components, see Fig. [Panel layout (Subdivision Surface as an example).](#fig-modifiers-panel-layout).

[image reference removed]

Panel layout (Subdivision Surface as an example).

At the top is the panel header.
The icons each represent different settings for the modifier (left to right):

/ Expand
:   Collapse modifier to show only the header and not its options.

Type
:   An icon as a quick visual reference of the modifier’s type.

Name
:   Every modifier has a unique name per object. Two modifiers on one object must have unique names,
    but two modifiers on different objects can have the same name. The default name is based on the modifier type.

On Cage Meshes
:   Depends on the previous setting, if enabled, the modified geometry can also be edited directly,
    instead of the original one.

Apply On Spline Curves Surfaces Text
:   Apply the whole modifier stack up to and including that one on the curve or surface control points,
    instead of their tessellated geometry.

Edit Mode
:   Display the modified geometry in Edit Mode, as well as the original geometry which you can edit.

/ Realtime
:   Toggle visibility of the modifier’s effect in the 3D Viewport.

/ Render
:   Toggle visibility of the modifier’s effect in the render.

Extras
:   Apply `Ctrl`-`A`
    :   Makes the modifier “real”: converts the object’s geometry to match the applied modifier’s results,
        and deletes the modifier.

        When applying a modifier to an object that shares Object Data between multiple objects,
        the object must first be made a [Single User](../../files/data_blocks.xhtml#data-system-datablock-make-single-user)
        which can be performed by confirming the pop-up message.

    Apply as Shape Key
    :   Stores the result of that modifier in a new relative [shape key](../../animation/shape_keys/introduction.xhtml)
        and then deletes the modifier from the modifier stack.
        This is only available with modifiers that do not affect the topology (typically, *Deform* modifiers only).

    Save as Shape Key
    :   Stores the result of that modifier in a new relative [shape key](../../animation/shape_keys/introduction.xhtml)
        and keeps the modifier in the modifier stack.
        This is only available with modifiers that do not affect the topology (typically, *Deform* modifiers only).

    Duplicate `Shift`-`D`
    :   Creates a duplicate of the modifier just below current one in the stack.

    Copy to Selected
    :   Copies the modifier from the [Active](../../glossary/index.xhtml#term-Active) object to all selected objects.

    Move to First/Last
    :   Moves the modifier to the first or last position in the modifier stack.

    Pin to Last
    :   Keeps the modifier at the end of the modifier stack.
        When a modifier is pinned, a pin icon will be displayed on the right side of the panel’s header.

    Move to Nodes
    :   Converts the existing [Geometry Nodes Modifier](geometry_nodes.xhtml)
        node tree to a group node to be reused in other node trees.
        See [Move to Nodes Operator](geometry_nodes.xhtml#bpy-ops-object-geometry-nodes-move-to-nodes) for more information.

        This operator is only available for the Geometry Nodes Modifier.

Delete `X`, `Delete`
:   Delete the modifier.

(Move)
:   Move the modifier up/down in the [stack](#modifier-stack),
    changing the evaluation order of the modifiers.

    A modifier is not movable if [Pin to Last](#bpy-types-modifier-use-pin-to-last) is enabled.

Below this header, all of the options unique to each modifier will be displayed.

### The Modifier Stack

Modifiers are a series of non-destructive operations which can be applied on top of an object’s geometry.
You can be apply them in almost any order.
This kind of functionality is often referred to as a “modifier stack”
and is also found in several other 3D applications.

In a modifier stack, the order in which modifiers are applied has an effect on the result.
Therefore the modifiers can be re-arranged by clicking  (grip icon) in the top right,
and moving the selected modifier up or down.
For example, the image below shows [Subdivision Surface](generate/subdivision_surface.xhtml)
and [Mirror](generate/mirror.xhtml) modifiers that have switched places.

Modifier Stack example.

|  |  |
| --- | --- |
| ../../_images/modeling_modifiers_introduction_mirror-subdiv2.png   The Mirror modifier is the last item in the stack and the result looks like two surfaces. | ../../_images/modeling_modifiers_introduction_mirror-subdiv1.png   The Subdivision Surface modifier is the last item in the stack and the result is a single merged surface. |

Modifiers are calculated from top to bottom in the stack.
In this example, the desired result (on right) is achieved by first mirroring the object,
and then calculating the subdivision surface.

#### Active Modifier

A modifier in the stack can be selected to mark in as [Active](../../glossary/index.xhtml#term-Active),
the active modifier displays an outline around the modifier’s panel.
To set an active modifier, select an area of the modifier’s panel background,
the modifier’s icon, or, select a modifier in the [Outliner](../../editors/outliner/index.xhtml).

The active modifier is used by the [Geometry Node Editor](../../editors/geometry_node.xhtml)
to determine which node group is being modified.