Bone Edit Snapper

Author: Melowilo Animation

Blender Version: 3.2.0+

Category: Armature, Skinning, Rigging

Location: View3D > UI > BoneSnap Tab

It is free, but if you find this useful and use it regularly, it would be appreciated if you could give something towards it. It will help our little indie project. If you can't give something towards it, don't worry, just grab it :) Otherwise you can support me by looking at my other paid for Blender addons, particularly Vertex Skin Weights that would make a perfect complement to this tool for rigging, if you are a rigger, OR Animation Snapper Pro, if you are an animator...OR BOTH if you do both ;D

Description

The "Bone Edit Snapper" addon for Blender streamlines the process of creating and aligning Edit Bones within an Armature. It allows you to:

• Snap selected Edit Bones to the location and orientation of a "Source Item" (which can be another Object or a Pose Bone from any Armature).
• Create new Edit Bones at the location and orientation of a "Source Item".
• Batch Create multiple Edit Bones, each corresponding to an item in a "Source List".

Control the *length** and alignment axis of the snapped/created bones.

Automatically *align the roll** of new/snapped bones to match the source's orientation for more intuitive posing.

Optionally *skin** the source mesh(es) to the newly created/snapped bone(s) with 100% weight, automatically setting up vertex groups and armature modifiers if needed.

This addon is particularly useful for quickly setting up control bones, helper bones, or any bone that needs to be precisely aligned with existing geometry or other rig components.

Features

Flexible Single Source Definition:

• Drag & Drop any Object or Armature to the "Source Drag & Drop" field.
• Use "Pick Source Bone" (eyedropper) to select a Pose Bone in the viewport.
• Use "Set as Source" to use the currently active Object, Pose Bone, or Edit Bone.

Batch Bone Creation:

• Maintain a list of source Objects.
• Create a new Edit Bone for each item in the list with a single click.
• Manage the list (add selected objects, remove, clear, reorder).

Precise Alignment & Length Control:

• Set a target length for new bones.
• Option to keep the current length of an existing bone when snapping.
• Align the bone's tail along the X, Y, or Z axis (or their negatives) of the Source Item or World Space.

Automatic Roll Alignment:

Option to automatically calculate and set the bone's roll to match the source's orientation, ensuring the bone's local Z-axis is sensibly aligned. This helps with IK pole targets and FK rotations.

Automatic Skinning:

• Optional one-click skinning of the source MESH object(s) to the target bone(s).
• Creates vertex groups and assigns 100% weight for all vertices.
• Adds an Armature modifier to the mesh if one doesn't exist or doesn't target the correct armature.

Context-Sensitive UI:

• Operators are enabled/disabled based on the current context (e.g., Armature Edit Mode, active bone, defined source).
• Informative messages guide the user.

Installation

1. Download the .zip.

2. In Blender, go to Edit > Preferences > Add-ons.

3. Click Install... and navigate to the downloaded .py or .zip file.

4. Enable the addon by checking the box next to "Bone Edit Snapper" in the add-ons list.

Usage

The addon panel can be found in the 3D Viewport:

View3D > UI > BoneSnap Tab (Press N in the 3D View to open the sidebar if it's hidden).

General Workflow:

1. Select an Armature and enter Edit Mode. All operations require you to be in Armature Edit Mode.

2. Define a Source:

For Single Bone Operations:

• Drag an object (or armature) onto the "Source Drag & Drop" field.
• Or, click the "Pick Source Bone" icon (eyedropper) and then click on a pose bone in the 3D View.
• Or, select an object, pose bone, or edit bone and click "Set as Source".
• The panel will display what is currently set as the single source.

For Batch Bone Creation:

• Select one or more objects in the 3D View that you want to use as sources.
• Click the + (Add) button next to the "Batch Source List" to add them to the list.
• You can manage the list using the Remove, Clear, Move Up, and Move Down buttons.

3. Adjust Settings:

• Target Bone Length: Set the desired length for newly created bones or for snapped bones if "Keep Current Length" is off.
• Keep Current Length: If snapping an existing bone, check this to maintain its original length.
• Align Tail Along: Choose which axis of the source (or world) the bone's tail should point along.
• Using Space: Choose "Source Item Local" to use the source's local axes for alignment, or "World Space" for global axes.
• Align Roll to Source: (Recommended: On) Check to automatically orient the bone's Z-axis based on the source's orientation.
• Skin Sources 100%: Check if you want the source mesh(es) to be automatically skinned to the bone(s) being created/snapped.

4. Perform Actions:

• Snap Active Edit Bone: (Requires an Edit Bone to be active/selected) Snaps the active Edit Bone to the defined "Single Source Item".
• Create Bone on Source: Creates a new Edit Bone based on the defined "Single Source Item" and settings.
• Create Bones on Source List: Creates a new Edit Bone for each item in the "Batch Source List" using the current settings.

UI Panel Sections:

Single Source Item:

• Displays the currently defined single source for snapping/creating one bone.
• "Pick Source Bone" (Eyedropper): Click to enter a modal operator to select a pose bone in the viewport as the source.
• "Set as Source" (Selection Icon): Sets the currently active Blender selection (Object, Pose Bone, or Edit Bone) as the source.
• "Source Drag & Drop": Drag an Object or Armature here. If an Armature is dragged and it's in Pose Mode with an active bone, that bone will be pre-selected.

Batch Source List:

A list to hold multiple source objects for batch bone creation.

• + (Add): Adds currently selected objects (in Object Mode) to the list.
• - (Remove): Removes the highlighted item from the list.
• ▲ (Move Up): Moves the highlighted item up in the list.
• ▼ (Move Down): Moves the highlighted item down in the list.
• X (Clear): Clears all items from the list.

Snapping & Creation Settings:

• Target Bone Length: The length for newly created bones, or for snapped bones if Keep Current Length is off.
• Keep Current Length: When snapping an existing bone, checking this preserves its current length instead of using Target Bone Length.
• Align Tail Along: Determines the direction of the bone's tail relative to its head. X, Y, Z, -X, -Y, -Z
• Using Space:
  • Source Item Local: Alignment axis is relative to the source item's local orientation.
  • World Space: Alignment axis is relative to the global world orientation.
• Align Roll to Source: If checked, the addon attempts to orient the bone's Z-axis (roll) to match the source object's orientation for better default bone rotations.
• Skin Sources 100%: If checked, any source Mesh object will be skinned to its corresponding bone.
  • An Armature Modifier will be added/configured on the mesh.
  • A Vertex Group named after the bone will be created/used.
• All vertices of the mesh will be assigned 100% weight to this group.

Operators:

• Snap Active Edit Bone: Snaps the currently active edit bone to the "Single Source Item".
• Create Bone on Source: Creates a new edit bone based on the "Single Source Item".
• Create Bones on Source List: Creates new edit bones for every item in the "Batch Source List".
• Operator Availability Info:
  • This section provides feedback on why certain operators might be disabled (e.g., not in Armature Edit Mode, no source defined).

Notes

• Ensure you are in *Edit Mode** for an Armature object before using the snapping or creation operators.
• For skinning to work, the source item(s) must be of type MESH.
• The "Align Roll to Source" feature tries its best to find a sensible roll. It prioritizes the source's Z-axis, then X, then Y, and finally global axes as fallbacks if the source axes are collinear with the bone's primary direction.

Known Issues / Limitations

(None currently identified for v1.1.0)

Contributing / Feedback

If you find bugs or have suggestions for improvements, please raise an issue on the repository where you found this addon, or contact the author.