IK Settings

1.7.0

When controlling the bones, basically you control by rotating the bones.
Sometimes, on the other hand, the user moves one bone and the other is automatically rotated.
This method is called IK (Inverse Kinematics).
IK allows intuitive control.
AnyPortrait provides both (1) IK control functions for editor editing and (2) IK functions that can be called from the game.
This page describes the settings for using IK and how to use it in the editor.
Bones with IK enabled Scripts used in this game can be found on the related page.

Bone Details UI

Before setting up the IK, the bone details UI is explained.
The bone information UI is divided into three tabs.

This screen shows the common options and the "Basic Properties" tab.
1. Name: Sets the name.
2. Sub-tabs: Tabs that categorize the bone's property UI elements.
3. Base Pose Transformation: Allows you to set the base position, rotation, and scale values.
4. Shape: Sets the shape and color displayed in the editor. Checking the "Helper" option displays only the bone's position.
5. Hierarchy: Displays parent-child bone connections and allows you to modify them. Clicking "Snap to Child Bone" snaps the end of the bone to the child bone.
6. Mirror Bone: Allows you to specify a bone that operates symmetrically to this one.
7. Other Properties: Configures additional properties, such as sockets. (Related Page)
8. Duplicate: Duplicates the bone.
9. Remove Bone: Reomoves the bone.

This is the "IK and Constraints" tab.
You can find the UI elements covered on this page within this tab.
1. IK Chain Type : Changes the IK chain type (Single, Head, Chain, Disabled).
2. IK Chain Connection Info : Displays information such as the start, end, and next connected bones of the IK chain; allows you to change the IK chain target.
3. Rotation Limit Options : Sets the rotation limits used during IK calculations. (Related Page)
4. IK Initial Pose : Sets the initial pose referenced during IK calculations.
5. IK Controller Settings : Configures the IK controller that operates continuously. (Related Page)
6. Constraints : Adds and configures constraints that limit bone transformations. (Related Page)
7. Final Rotation Correction : An option to apply additional bone rotation during the final stage of IK processing. (Related Page)

This is the screen for the "Physics" tab.
1. Jiggle Bone : Configures "Jiggle Bones" that move based on inertia. (Related Page)

Create an IK chain

When you deal with this IK setting professionally, you need a lot of options and it can be difficult.
To make IK fast and easy, AnyPortrait provides "IK Chain" and "IK Mode" methods.

Concept illustration of IK chain.
The IK chain consists of Head, Chain, and Target.
IK is calculated from the position of the Target bone with the Head bone as the starting point.

For IK chains, the bone has one of four IK modes.
1. Single : The state of the Head with the target directly attached without a chain. This is the default for all bones with child bones.
2. Head : The starting point of the IK chain.
3. Chain : The state of the intermediate bones in the IK chain. All bones between Head and Target are in Chain mode, which is forced.
4. Disabled : Not in the IK chain. There is no child bone or is arbitrarily specified.

To create an IK chain,
(1) select the bone to be the Head of the IK chain,
(2) change the IK mode to Head.

(3) Press the Change IK Target button to (4) select the child to be targeted.

When the IK chain is created, the middle bones are automatically changed to Chain mode.
The target bone is not affected by the IK chain itself.
(Currently, there is no child bone, which is Disabled mode, but you can also configure a new IK chain.)

With the IK chain in place, you can see that the bones in the chain rotate automatically as you move the bone.
(You can also check in bone editing, modifiers, and animations.)

IK Angle Constraint

IK calculation, you may want to limit the angle depending on the joint.

Here's how to use the ability to limit the angle of rotation.
(1) Select the bone in the IK chain to limit the rotation angle.
(2) Press the Constraint button to enter the Constraint On state.

1.7.0

UI layout and terminology have changed in AnyPortrait v1.7.0.
The "IK Angle Constraint" item has been changed to "Rotation Limit Options" under "IK Rotation Options."
The item for limiting the angle is named "Limit Rotation" and has been updated to a checkbox-style UI.

Sets the rotation limit range.
You can set the limit range with Min and Max values.
The Preferred value is the angle that is the basis of the IK calculation expression.
Bones with angle constraint can be viewed intuitively on the screen.

IK angle constraints can be found in the modifier or animation.
(Note : Since it is a function of limiting the rotation deformation value, it is not possible to check on the mesh group-Bone tab.)
When you work on a modifier or animation, you can see that the angle-limited IK is executed as in the above screen.

This setting also applies to games.

1.5.0

Added options related to IK angle constraints.
1. Soft Limit is an option that applies rotation angle constraints a little loosely to make the bone move naturally.
2. Initial Pose is an option for the pose that IK calculations initially refer to.

These options work when the IK method is set to FABRIK. (Related page)
For more information, please refer to the following manual.
- Making IK work as intended

Bone without IK

There are cases where IK should not be applied.
In the following cases, the parent bone is not related to the IK chain relationship.

- If there is no parent bone
- If the parent bone is in Disabled mode
- If the parent bone has an IK chain but is targeted to another child bone

The above picture shows that the parent bone has an IK chain but the IK chain is not formed because the IK chain is formed for the other child bone.

If IK is not set, the parent bone will not rotate.