How to Use Deformers

Deformers give the ability to animate objects and parts of a character model using computer generated deformations. This allows you to bend or distort drawings without having to redraw them. When used in cut-out animation, they can extend considerably the range of movements and poses a character model can pull without having any of its parts drawn in different poses, which can save a lot of time and make your cut-out animation look much more natural with little effort.

Deformers can be used to deform a single drawing layer or a hierarchy of layers, so a single deformer can be used to deform anything ranging from a simple prop to a whole character rig. They can be used on both vector and bitmap drawings.

Deformers work by rigging them as a parent of the drawing you wish to deform, building the deformer structure, then animating it. This can be easily done using the Rigging tool.

There are four types of deformers available in Harmony Premium:

  • Bone
  • Game Bone
  • Curve
  • Envelope

Bone Deformer

The Bone deformation allows you to create a bone-like structure in which each part is solid, but with articulations that are flexible. This is mostly useful for animating a character's limbs, such as the arms or legs, or other parts that can be articulated such as torsos or fingers. For example, a Bone deformation can be used to articulate an arm that is made of a single drawing, so that the upper arm and forearm can be moved independently, without having to draw the upper arm and the forearm on different layers. Harmony will deform the drawing to make it look articulated. The different parts of a Bone deformation can be rotated around their joint, extended and shortened, giving you the same capabilities as animating articulations on different layers, without having to worry about parts detaching, pivot points, or clipping outlines.

Curve Deformer

The Curve deformation allows you to deform parts of a character using a vector curve. By manipulating the curve's points and their bezier handles, you can change the curve's direction, shape and length, and Harmony will deform the drawing to match the curve's shape. Curve deformations are mostly used to animate elements that don't have joints, such as hair bangs or facial features, or body parts with so many joints that they seem curved, such the torso. They can also be used to animate the limbs of characters in a rubber hose style of animation, where arms and legs are bent in curves.

Envelope Deformer

The Envelope deformation allows you to deform an image using Bezier handles located all around the contour of the shape. Envelope deformation chains are composed of Curve deformation nodes. It is regularly used to deform shapes, such as hair, cloak, shoulder shape, head shape and so on. You can use the Envelope deformation to deform a drawing so it looks like it changes from a profile view to a front view to create head and character rotations using only one set of drawings.

The main differences between the Curve and Envelope deformers is that the Envelope chain can be closed by connecting the last Curve deformation node to the initial Offset point. Once connected, the Offset point no longer repositions the entire chain, only its own control point.

NOTE It's not recommended to use the Envelope deformations on bitmap images and textures.

Game Bone Deformer

The Game Bone deformation is very similar to the Bone deformation. It allows you to create a bone-like structure in which each part is solid, but with articulations that are flexible. However, it is optimized for game engines such as Unity. Hence, it is usually only used for game development and not in animated productions. Contrary to the Bone deformations, Game Bone deformations do not have Bias and Region of Influence properties. The articulation folds also look slightly more rounded.

Creating Deformers

The most simple way of creating deformers is to use the Rigging tool, available in the Deformation toolbar. With this tool, all you need to do to create a deformer is to select the layer you wish to deform, then place each point of your deformer in the Camera view.

Deformers exist in your scene as a hierarchy of deformation nodes. When you create a new deformer, the first point you set is the deformer's root, and each new point you create is a child of the previous point. Deformers are hence created in a chain, and should be created with your character's hierarchy in mind. For example, when you create a deformer for an arm, the root should be the shoulder joint, the second point should be the elbow and the third should be the wrist.

Adding several deformers to your scene is liable to make its layer structure appear heavy in the Timeline and Node views, as every deformation point is a layer of its own. Hence, it is recommended to have the Automatically create a group when creating a new deformation rig option enabled in the Tool Properties view before building a deformer. This will create deformers within groups created specifically to contain their structure, making the resulting hierarchy appear a lot lighter.

Displaying Deformers

Harmony lets you control which deformers are displayed in the Camera view independently from the current selection. When you create a deformation chain, its deformation controls are displayed in the Camera view. However, if you select an existing deformer or a layer that's connected to existing deformers, its deformation controls won't display right away. Likewise, deselecting a deformation chain will not hide its deformation controls. Before you can animate or modify an existing deformation chain, you must manually display it.

Modifying Existing Deformation Chains

As you attempt to animate a deformation, or if you need to make changes to the drawings under a deformation, you may need to make adjustments to the deformation chain to better fit your needs.

Animating With Deformers

Just like with animating pegs and drawing layers, you can animate your deformers by creating keyframes on their corresponding layers in the Timeline. Animating deformers works exactly like making modifications to a deformer, except it requires using the Transform tool instead of the Rigging tool. When the Transform tool is selected, deformation controls in the Camera view display in green, which means they are in animation mode, whereas when the Rigging tool is selected, they display in red, meaning they are in rigging mode.