Create Assets

May 18, 2026 · View on GitHub

Source: src/mpfb/ui/create_assets/makerig/

Parent panel: MPFB_PT_Create_Panel ("Create assets")

Overview

MakeRig is the tool for developing and authoring custom rig definition files. While the Rigging section covers applying pre-built rigs to characters, MakeRig is intended for rig authors — people who want to create new rig definitions from scratch or modify existing ones, export them as JSON rig files, and manage the vertex weight files that accompany them.

MakeRig defines four panels (one root container plus three functional child panels). All four panels are parented to MPFB_PT_Create_Panel ("Create assets") and appear in the RIGCATEGORY sidebar tab.

Panels

MPFB_PT_MakeRig_Panel ("MakeRig")

Attribute	Value
`bl_label`	"MakeRig"
`bl_category`	`RIGCATEGORY`
`bl_parent_id`	`MPFB_PT_Create_Panel`
`bl_options`	`DEFAULT_CLOSED`
Base class	`Abstract_Panel`

This is a container panel. It draws no controls of its own; its sole purpose is to provide the collapsible parent that groups the three functional MakeRig panels together in the sidebar.

MPFB_PT_MakeRigBones_Panel ("Manage bones")

Attribute	Value
`bl_label`	"Manage bones"
`bl_category`	`RIGCATEGORY`
`bl_parent_id`	`MPFB_PT_MakeRig_Panel`
`bl_options`	`DEFAULT_CLOSED`
Base class	`Abstract_Panel`

Provides a tool for precisely positioning individual bone heads and tails to the centre of MPFB joint cubes. Joint cubes are small helper objects baked into the base mesh that mark anatomically significant joint locations (shoulder, elbow, knee, etc.). By snapping bone endpoints to these cubes you can ensure that the rig is always aligned correctly with any base mesh shape, regardless of applied morphs.

The "Move head/tail" box is shown only when:

The active object is an armature.
The armature is in Edit mode.
Exactly one bone is selected.
The basemesh is either a child of the armature or is also selected.

The two dropdowns (head_cube, tail_cube) list every available joint cube by name, plus special entries "Don't change" and "To closest". After choosing targets, pressing Move to cubes repositions the selected bone.

MPFB_PT_MakeRigIO_Panel ("Load/Save rig")

Attribute	Value
`bl_label`	"Load/Save rig"
`bl_category`	`RIGCATEGORY`
`bl_parent_id`	`MPFB_PT_MakeRig_Panel`
`bl_options`	`DEFAULT_CLOSED`
Base class	`Abstract_Panel`

Handles reading and writing rig definition files (JSON) and vertex weight files (JSON). Three boxes are drawn:

Load/Save rig — properties for controlling import/export behaviour (rig_parent, rig_subrig, rig_save_rigify, rig_refit) and buttons to load or save a rig JSON file.
Load/Save weights — properties for weight export (weights_mask, save_masks, save_evaluated) and buttons to load or save a weights JSON file.
Save to library — only shown when the active object is an armature. Name and identifying-bones fields, plus a "Save rig to library" button that installs the rig definition into the user's local asset library.

MPFB_PT_MakeRigWeights_Panel ("Manage weights")

Attribute	Value
`bl_label`	"Manage weights"
`bl_category`	`RIGCATEGORY`
`bl_parent_id`	`MPFB_PT_MakeRig_Panel`
`bl_options`	`DEFAULT_CLOSED`
Base class	`Abstract_Panel`

Provides a tool for automatically transferring vertex weights from one rig/character combination to another. This is useful when a new rig layout needs weights seeded from an existing, already-weighted rig.

The "Transfer weights" box is shown only when:

Exactly two armature objects are selected.
The active object is one of the two armatures.
Each armature has a basemesh as a child or nearby relative.

The panel labels which rig is the source (active) and which is the destination, then shows the Auto transfer weights button.

Operators

MPFB_OT_MoveBoneToCubeOperator

Attribute	Value
`bl_idname`	`mpfb.move_bone_to_cube`
`bl_label`	"Move to cubes"

Repositions the head and/or tail of the currently selected bone to the centre of the joint cubes specified by head_cube and tail_cube. Only available in armature Edit mode with exactly one bone selected.

MPFB_OT_LoadRigOperator

Attribute	Value
`bl_idname`	`mpfb.load_rig`
`bl_label`	"Load rig"

Opens a file browser and imports a rig definition JSON file, creating an armature in the scene. The rig_parent and rig_subrig properties control whether the new rig is parented to an existing object or created as a sub-rig.

MPFB_OT_SaveRigOperator

Attribute	Value
`bl_idname`	`mpfb.save_rig`
`bl_label`	"Save rig"

Opens a file browser and exports the active armature to a rig definition JSON file. The rig_save_rigify property controls whether Rigify layer metadata is included. The rig_refit property controls whether a refit operation is performed after saving.

MPFB_OT_LoadWeightsOperator

Attribute	Value
`bl_idname`	`mpfb.load_weights`
`bl_label`	"Load weights"

Opens a file browser and imports a vertex weight JSON file onto the basemesh associated with the active armature.

MPFB_OT_SaveWeightsOperator (makerig)

Attribute	Value
`bl_idname`	`mpfb.save_weights`
`bl_label`	"Save weights"

Opens a file browser and exports the vertex weights of the basemesh associated with the active armature to a JSON file. The weights_mask property selects which rig the weights are exported for; save_masks controls whether mask vertex groups are included; save_evaluated controls whether the evaluated (post-modifier) mesh is used as the source.

MPFB_OT_SaveRigToLibraryOperator

Attribute	Value
`bl_idname`	`mpfb.save_rig_to_library`
`bl_label`	"Save rig to library"

Saves the active armature as a named rig into the user's local MPFB asset library. The library_rig_name property sets the name; library_identifying_bones is a comma-separated list of bones that uniquely identify the rig type (used when auto-detecting a rig on import); library_also_save_weights controls whether the associated weight file is also written to the library.

MPFB_OT_AutoTransferWeightsOperator

Attribute	Value
`bl_idname`	`mpfb.auto_transfer_weights`
`bl_label`	"Auto transfer weights"

Automatically copies vertex weights from the source rig's basemesh to the destination rig's basemesh. The source rig is the active armature; the destination is the other selected armature. Uses nearest-vertex mapping for the transfer.

Properties

MakeRig uses MakeRigProperties (prefix "MRP_"), combining JSON-defined properties from makerig/properties/ with several additional properties defined in code in makerig/__init__.py.

From JSON files

Property	Type	Description
`rig_parent`	boolean	Make the loaded rig the parent of the basemesh.
`rig_subrig`	boolean	Treat the loaded rig as a sub-rig rather than a primary rig.
`rig_save_rigify`	boolean	Include Rigify layer metadata when saving the rig.
`rig_refit`	boolean	Refit the rig to the basemesh after saving.
`weights_mask`	enum	Which rig type the weights are associated with (used to filter when multiple rigs are present).
`save_masks`	boolean	Include mask vertex groups in the exported weight file.
`save_evaluated`	boolean	Use the evaluated (post-modifier) mesh when exporting weights.
`head`	boolean	Update the head bone when repositioning.

Defined in code

Property	Type	Description
`head_cube`	enum (dynamic)	Joint cube to snap the selected bone's head to. Populated from the base mesh's `joint-*` vertex groups. Special options: "Don't change" and "To closest".
`tail_cube`	enum (dynamic)	Joint cube to snap the selected bone's tail to. Same options as `head_cube`.
`library_rig_name`	string	Alphanumeric name (letters, digits, underscores) for the rig when saving to library.
`library_identifying_bones`	string	Comma-separated bone names that uniquely identify this rig type.
`library_also_save_weights`	boolean	Also save the associated weight file when saving the rig to library. Default: true.

Rigging — Custom rig — apply a finished custom rig definition to a character
MakeWeight — standalone weight editing tools (truncation, symmetrisation, import/export)
RigService — the service underlying rig loading and saving