Manual/Hooks
From BlenderWiki
Hooks are similar to Shape Keys
in that they deform a mesh over time (frames). The difference is that
hooks make it look like the mesh is snagged with a fish hook. Moving
the hook moves selected vertices under the influence of the hook (which
is really just an Empty), and you make the hook move by animating the
motion of the empty through Ipo keys. As the hook moves, it pulls
weighted vertices from the mesh with it. If you have used Proportional
Editing, you can think of it as animated proportional editing. While
hooks do not give you the fine control over vertice movement that Shape
Keys do, they are much simpler to use.
Object Hooks
Mode: Object Mode / Edit Mode
Panel: Editing Context → Modifiers
Hotkey: Ctrl H
Menu: Mesh → Vertices → Add Hook
Description
Hooks give access at object level to the underlying geometry of meshes, curves, surfaces or lattices. A hook is an object feature and it is like a parent to an object, but for vertices. You can create as many hooks to an object as you like, and assign for each hook vertices that will be affected. Overlapping hooks is also possible, here a weighting factor per hook is provided that determines the amount each hook will affect the overlapping vertices.
All object level options and transformations are possible on the hook object, including using hierarchies, constraints, ipo and path animations. You can also make the hook-parent a child of the original object if you don't want object transformations to deform the hooks.
Note: When you change topology (i.e. more destructive editing than just manipulating existing points), you most likely have to reassign existing hooks as well. |
Examples
A typical example of using Hooks is to animate vertices or groups of vertices. For example, you may want to animate the vertices associated with a "Mouth" on a character's face.
In (Animated face frame 1) and (Animated face frame 10) a face made from Bezier curves has two Hooks applied. One applied to a control-point on the mouth labeled "A" and one applied to the eyebrow labeled "B". The animation has 10 frames over which Hook A moves up and Hook B moves down.
Adding Hooks
Mode: Edit Mode
Panel: Editing Context → Modifiers
Hotkey: Ctrl H
Menu: Mesh → Vertices → Add Hook
Description
Since hooks relate to vertices or control points, most editing options are available in edit mode for meshes, curves, surfaces and lattices.
Options
- Add, New Empty
- Adds a new hook and create a new empty object, that will be a parent to the selection, at the center of the selection
- Add, To Selected Object
- When another object is selected (you can do that in edit mode with Ctrl RMB
) the new hook is created and parented to that object
Editing Hooks
Mode: Edit Mode
Panel: Editing Context → Modifiers
Hotkey: Ctrl H
Menu: Mesh → Vertices → Add Hook
Description
Once hooks are available in an object, the hook menu will give additional options:
Options
- Remove
- This will give a new menu with a list of hooks to remove
- Reassign
- Use this if you want to assign new vertices to a hook
- Select...
- Select the vertices attached to a specific hook
- Clear Offset...
- Neutralize the current transformation of a hook parent
Hook Modifier
Mode: Object Mode / Edit Mode
Panel: Editing Context → Modifiers
Hotkey: Ctrl H
Description
Hooks are modifiers, that are added to the modifier stack. For each hook modifier, you can give a hook a new name, the default name is the parent name, give it a new parent by typing the new parents name or assign it a Force weighting factor.
Options
In the editing buttons, modfier panel, when a hook is created, you can control it via the panel.
- Ob
- The parent object name for the Hook. Changing this name also recalculates and clears offset
- Reset
- Recalculate and clear the offset transform of Hook
- Recenter
- Set Hook center to cursor position
- Select
- Select affected vertices on mesh
- Reassign
- Reassigns selected vertices to this hook
- Force
- Since multiple hooks can work on the same vertices, you can weight the influence of a hook this way. Weighting rules are:
- If the total of all forces is smaller than 1.0, the remainder, 1.0-forces, will be the factor the original position have as force.
- If the total of all 'forces' is larger than 1.0, it only uses the hook transformations, averaged by their weights.
- Falloff
- If not zero, the falloff is the distance where the influence of a hook goes to zero. It currently uses a smooth interpolation, comparable to the Proportional Editing Tools. (See mesh_modeling_PET)
|