Developer

Source: src/mpfb/ui/developer/

Overview

The Developer section contains panels and operators intended for use by addon developers and maintainers — not by end users working on characters. It provides four main capabilities:

• Logging controls — inspect and adjust the verbosity of MPFB's internal logging channels at runtime, and export log files for review outside of Blender.
• Node tree I/O — serialize an object's material node tree to a JSON file, or reconstruct a node tree on an object from a saved JSON file.
• Target file I/O — import one or more MakeHuman .target files as shape keys on a basemesh, or export an active shape key back to a target file.
• Code generation — a set of dangerous tools that write Python source files directly into the addon directory. These are used when maintaining the v2 node model layer (creating new primitives, composites, or material wrappers).

Unlike most MPFB sections, the Developer category has two separate panel surfaces:

• MPFB_PT_Developer_Panel appears in the 3D Viewport sidebar under the Developer tab and provides logging, node I/O, target I/O, and test utilities.
• MPFB_PT_Node_Developer_Panel appears in the Shader Node Editor sidebar under the same tab and provides node group and material code-generation tools.

Both panels share the same set of scene properties, loaded from the properties/ directory with the prefix DEV_.

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Panels

MPFB_PT_Developer_Panel ("Developer")

Source: src/mpfb/ui/developer/developerpanel.py

Attribute	Value
bl_label	"Developer"
bl_space_type	VIEW_3D
bl_region_type	UI
bl_category	DEVELOPERCATEGORY
bl_options	{'DEFAULT_CLOSED'}
Base class	bpy.types.Panel (not Abstract_Panel)
Poll	none — always visible when the Developer tab is open

This is the root panel for the Developer section in the 3D Viewport. It does not inherit from Abstract_Panel; it is a plain bpy.types.Panel subclass. There is no poll method, so it is always shown when the Developer sidebar tab is active.

The panel draws five labelled boxes:

"Log levels"

Controls for reading and overriding individual log channel verbosity.

• Button: mpfb.list_log_levels — prints all logger names and current levels to the console.
• Button: mpfb.reset_log_levels — removes all log level overrides and resets the default to INFO.
• Property: loggers_filter — filter dropdown to narrow the logger list by category.
• Property: available_loggers — dropdown listing all loggers that match the current filter; selecting "default" targets the global default level.
• Property: chosen_level — the log level to apply.
• Button: mpfb.set_log_level — applies the chosen level to the selected logger.

"Export log file"

Copies a log file to a user-specified location.

• Label: "Use default for combined log" (reminder that selecting "default" from the logger list exports the combined log).
• Property: available_loggers — selects which logger's log file to export.
• Button: mpfb.export_log — opens a file browser and copies the log file to the chosen path.

"Load/save nodes"

Transfers a material's node tree between Blender and a JSON file.

• Button: mpfb.save_nodes — serializes the active object's material node tree to a .json file.
• Button: mpfb.load_nodes — reads a .json file and creates a new material from it on the active object.
• Button: mpfb.rewrite_node_types — dangerous code generation: regenerates all primitive node wrapper source files in the addon directory.

"Load/Save targets"

Moves MakeHuman morphing target data in and out of Blender as shape keys.

• Button: mpfb.load_target — imports one or more .target files as shape keys on the basemesh.
• Button: mpfb.save_target — exports the active shape key on the basemesh back to a .target file.

"Unit tests"

• Label: "See README in test dir" (reminder to read test/README before running tests).
• Button: mpfb.unit_tests — invokes pytest on the addon's test directory and reports the result code.

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MPFB_PT_Node_Developer_Panel ("Node developer")

Source: src/mpfb/ui/developer/nodedeveloperpanel.py

Attribute	Value
bl_idname	NODE_PT_mpfb_node_developer_panel
bl_label	"Node developer"
bl_space_type	NODE_EDITOR
bl_region_type	UI
bl_category	DEVELOPERCATEGORY
bl_options	— (not set, defaults to empty)
Base class	Abstract_Panel
Poll	visible only when context.area.ui_type == "ShaderNodeTree"

This panel lives in the Shader Node Editor rather than the 3D Viewport. It is only shown when the node editor is displaying a shader node tree (i.e. not a geometry node tree or compositor). It shares DEVELOPER_PROPERTIES with the main developer panel.

The panel draws two labelled boxes:

"Groups"

Tools for managing MPFB's v2 node groups in the current Blender file.

• Button: mpfb.write_composite — dangerous code generation: reads the selected node group and writes a new composite wrapper Python file plus test file into the addon's source tree.
• Button: mpfb.create_groups — calls NodeService.ensure_v2_node_groups_exist() to create any missing v2 node groups.
• Button: mpfb.destroy_groups — removes all node groups whose names start with "mpfb" from the Blender file.

"Materials"

Tools for generating v2 material wrapper Python code from the currently open shader node tree.

• Property: mhmat_based — when enabled, the generated code includes conditional logic that reads values from a MakeHuman .mhmat material file.
• Property: output_material_name — the name used for the generated Python class and output files.
• Button: mpfb.write_material — dangerous code generation: writes a new material wrapper Python file plus test file into the addon's source tree.
• Button: mpfb.replace_with_skin — wipes the currently open node tree and inserts MPFB's built-in v2 skin material (NodeWrapperSkin).

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Properties

Properties are loaded from JSON files in src/mpfb/ui/developer/properties/ using SceneConfigSet.from_definitions_in_json_directory() with the prefix DEV_. Two additional enum properties are added programmatically and populated at runtime by LogService.

Scene properties (from JSON)

Property	Type	Default	Description
chosen_level	enum	"3" (INFO)	The log level to apply when clicking "Set log level". Options: CRASH (0), ERROR (1), WARN (2), INFO (3), DEBUG (4), TRACE (5), DUMP (6).
output_material_name	string	"MpfbMaterial"	Name for the Python class and output files generated by the material and composite code-generation operators.
mhmat_based	boolean	False	When True, the write-material operator generates code that reads .mhmat texture and parameter values to conditionally build nodes and links.

Dynamically populated properties

These are added via SceneConfigSet.add_property() and populated by callback functions that call LogService at draw time:

Property	Type	Description
available_loggers	enum	All currently registered logger channels, filtered by loggers_filter. Selecting "default" targets the global default log level rather than a named channel.
loggers_filter	enum	Category filter for available_loggers. The items are derived from the prefix portions of all logger names. Changing this value narrows the available_loggers list.

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Operators

MPFB_OT_List_Log_Levels_Operator

Source: src/mpfb/ui/developer/operators/listloglevels.py

Attribute	Value
bl_idname	mpfb.list_log_levels
bl_label	"List log levels"
bl_options	{'REGISTER'}
Base class	MpfbOperator
Poll	none

Iterates every registered logger, sorts them alphabetically, and prints each name along with its current effective level to the Python console. Loggers that have had no explicit override show "(default)" instead of a level name. Useful for auditing which channels are active and at what verbosity.

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MPFB_OT_Reset_Log_Levels_Operator

Source: src/mpfb/ui/developer/operators/resetloglevels.py

Attribute	Value
bl_idname	mpfb.reset_log_levels
bl_label	"Reset log levels"
bl_options	{'REGISTER'}
Base class	MpfbOperator
Poll	none

Calls LogService.reset_log_levels(), which removes all per-channel overrides and sets the global default level back to INFO. Useful for clearing noisy debug settings without restarting Blender.

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MPFB_OT_Set_Log_Level_Operator

Source: src/mpfb/ui/developer/operators/setloglevel.py

Attribute	Value
bl_idname	mpfb.set_log_level
bl_label	"Set log level"
bl_options	{'REGISTER'}
Base class	MpfbOperator
Poll	none

Reads the available_loggers and chosen_level scene properties, then calls LogService.set_level_override() for the named channel, or LogService.set_default_log_level() if the selected logger is "default". The change takes effect immediately for all subsequent log calls on that channel.

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MPFB_OT_Export_Log_Operator

Source: src/mpfb/ui/developer/operators/exportlog.py

Attribute	Value
bl_idname	mpfb.export_log
bl_label	"Export log"
bl_options	{'REGISTER'}
Base class	MpfbOperator, ExportHelper
Poll	none

Opens a file-save dialog (.txt extension). After the user chooses a destination, the operator reads the available_loggers scene property to decide which log file to copy. Selecting "default" copies the combined log file (which aggregates all channels). Any other selection copies the log file for that specific channel. The file is copied using shutil.copy().

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MPFB_OT_Save_Nodes_Operator

Source: src/mpfb/ui/developer/operators/savenodes.py

Attribute	Value
bl_idname	mpfb.save_nodes
bl_label	"Save nodes"
bl_options	{'REGISTER'}
Base class	MpfbOperator, ExportHelper
Poll	active object must exist and have exactly one material

Opens a file-save dialog (.json extension). Reads the active object's material node tree via NodeService.get_node_tree_as_dict() and writes the result as an indented, sorted JSON file. The JSON captures all nodes, their properties, and the links between them in a format that mpfb.load_nodes can reconstruct.

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MPFB_OT_Load_Nodes_Operator

Source: src/mpfb/ui/developer/operators/loadnodes.py

Attribute	Value
bl_idname	mpfb.load_nodes
bl_label	"Load nodes"
bl_options	{'REGISTER'}
Base class	MpfbOperator, ImportHelper
Poll	active object must exist and must have no materials

Opens a file-open dialog (.json extension). Reads the JSON file previously saved by mpfb.save_nodes, replaces any $group_name placeholder strings with a timestamp-based unique identifier (so that loaded node groups do not collide with existing ones), then creates an empty material on the active object and reconstructs the node tree via NodeService.apply_node_tree_from_dict().

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MPFB_OT_Load_Target_Operator

Source: src/mpfb/ui/developer/operators/loadtarget.py

Attribute	Value
bl_idname	mpfb.load_target
bl_label	"Load targets"
bl_options	{'REGISTER', 'UNDO'}
Base class	MpfbOperator, ImportHelper
Poll	@pollstrategy(PollStrategy.BASEMESH_ACTIVE) — active object must be a basemesh

Opens a multi-file-select dialog accepting .target, .ptarget, .target.gz, and .ptarget.gz files. Each selected file is imported as a shape key on the basemesh via TargetService.load_target(). Two options are exposed in the file browser sidebar:

Property	Type	Default	Description
weight	float (0.0–1.0)	1.0	Initial weight assigned to each imported shape key.
encode	boolean	False	When enabled, target file names are encoded according to MPFB's macro detail naming rules, matching how built-in targets are named internally.

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MPFB_OT_Save_Target_Operator

Source: src/mpfb/ui/developer/operators/savetarget.py

Attribute	Value
bl_idname	mpfb.save_target
bl_label	"Save target"
bl_options	{'REGISTER'}
Base class	MpfbOperator, ExportHelper
Poll	active object must be a basemesh and must have an active (non-basis) shape key

Exports the active shape key as a MakeHuman-compatible target file. The operator pre-fills the file name by decoding the shape key name and stripping any macro detail prefix. It automatically chooses the .target.gz extension for shape keys whose names start with $md- (indicating a compressed macro detail target), and .target for all others. A panel in the file browser offers:

Property	Type	Default	Description
include_header	boolean	False	When enabled, a MakeTarget boilerplate comment header is prepended to the output file.

Supports writing both uncompressed .target / .ptarget files and gzip-compressed .target.gz / .ptarget.gz files.

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MPFB_OT_Create_Groups_Operator

Source: src/mpfb/ui/developer/operators/create_groups.py

Attribute	Value
bl_idname	mpfb.create_groups
bl_label	"Create groups"
bl_options	{'REGISTER'}
Base class	MpfbOperator
Poll	Shader Node Editor context (context.area.ui_type == "ShaderNodeTree")

Calls NodeService.ensure_v2_node_groups_exist(fail_on_validation=True), which checks that all MPFB v2 node groups are present in the current Blender file and creates any that are missing. Useful after loading a fresh .blend file or when a group has been accidentally deleted.

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MPFB_OT_Destroy_Groups_Operator

Source: src/mpfb/ui/developer/operators/destroygroups.py

Attribute	Value
bl_idname	mpfb.destroy_groups
bl_label	"Destroy Groups"
bl_options	{'REGISTER'}
Base class	MpfbOperator
Poll	Shader Node Editor context (context.area.ui_type == "ShaderNodeTree")

Iterates bpy.data.node_groups and removes every node group whose name starts with "mpfb" (case-insensitive). This is a destructive operation — it permanently removes the groups from the Blender file. Typically used before re-running mpfb.create_groups to obtain a clean rebuild of all v2 node groups.

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MPFB_OT_Replace_With_Skin_Operator

Source: src/mpfb/ui/developer/operators/replacewithskin.py

Attribute	Value
bl_idname	mpfb.replace_with_skin
bl_label	"Skin"
bl_options	{'REGISTER'}
Base class	MpfbOperator
Poll	Shader Node Editor context (context.area.ui_type == "ShaderNodeTree")

Clears the currently open node tree and replaces its entire content with MPFB's v2 skin material by calling NodeWrapperSkin.create_instance(node_tree). This is a destructive, in-place replacement — the previous node setup is lost. Primarily a convenience for quickly testing or inspecting the v2 skin material structure.

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MPFB_OT_Unit_Tests_Operator

Source: src/mpfb/ui/developer/operators/unittests.py

Attribute	Value
bl_idname	mpfb.unit_tests
bl_label	"Run unit tests"
bl_options	{'REGISTER'}
Base class	MpfbOperator
Poll	none

Invokes pytest programmatically on the addon's test/tests/ directory via LocationService.get_mpfb_test("tests"). Results are printed to the Python console. A non-zero pytest return code is surfaced as a Blender error report. Note that pytest must be installed in the Blender Python environment for this to work — see the test/ directory's README for setup instructions.

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MPFB_OT_Write_Composite_Operator

Source: src/mpfb/ui/developer/operators/writecomposite.py

Warning: This is a code generation utility. It writes Python source files directly into the addon's source tree at src/mpfb/entities/nodemodel/v2/composites/. Only use this if you are maintaining the MPFB node model.

Attribute	Value
bl_idname	mpfb.write_composite
bl_label	"Write composite"
bl_options	{'REGISTER'}
Base class	MpfbOperator
Poll	Shader Node Editor context, and exactly one ShaderNodeGroup node must be selected

Takes the currently selected node group in the shader node editor and generates two files:

1. entities/nodemodel/v2/composites/nodewrapper{groupname}.py — a Python class inheriting from AbstractGroupWrapper with _ORIGINAL_NODE_DEF, _ORIGINAL_TREE_DEF, and a setup_group_nodes() method that recreates all nodes and links.
2. test/tests/ddd_entities/nodemodel_v2_composites_{groupname}_test.py — a pytest test file with tests for availability, instantiation, and tree validation.

Links are written in three ordered passes: Group Input outgoing links first, then internal links, then links going into Group Output. This ordering ensures that links referencing nodes in the correct sequence.

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MPFB_OT_Write_Material_Operator

Source: src/mpfb/ui/developer/operators/writematerial.py

Warning: This is a code generation utility. It writes Python source files directly into the addon's source tree at src/mpfb/entities/nodemodel/v2/materials/. Only use this if you are maintaining the MPFB node model.

Attribute	Value
bl_idname	mpfb.write_material
bl_label	"Write material"
bl_options	{'REGISTER'}
Base class	MpfbOperator
Poll	Shader Node Editor context (context.area.ui_type == "ShaderNodeTree")

Reads the output_material_name and mhmat_based scene properties, then generates two files from the currently open shader node tree:

1. entities/nodemodel/v2/materials/nodewrapper{materialname}.py — a Python class inheriting from AbstractMaterialWrapper with _ORIGINAL_TREE_DEF and a setup_group_nodes() method. If mhmat_based is True, the generated node() and link() helpers include an optional mhmat_key parameter that conditions node/link creation on the presence of a matching key in a .mhmat file.
2. test/tests/03_entities/nodemodel_v2_material_{materialname}_test.py — a pytest test file with availability, instantiation, and validation tests.

When mhmat_based is True and a Principled BSDF node is present, the generated code also calls self.update_principled_sockets_from_mhmat(principled, mhmat) to propagate material values to the shader inputs.

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MPFB_OT_Rewrite_Node_Types_Operator

Source: src/mpfb/ui/developer/operators/rewritenodetypes.py

Warning: This is an extremely destructive code generation utility. It overwrites all primitive node wrapper source files in src/mpfb/entities/nodemodel/v2/primitives/ and regenerates primitives/__init__.py. Only use this when Blender has introduced new or changed shader node types that need to be reflected in the MPFB node model.

Attribute	Value
bl_idname	mpfb.rewrite_node_types
bl_label	"Rewrite node types"
bl_options	{'REGISTER'}
Base class	MpfbOperator
Poll	none

Iterates every known Blender shader node class (excluding ShaderNodeCustomGroup), instantiates each one in a temporary node tree, extracts its definition via NodeService.get_v2_node_info(), and writes a nodewrapper{classname}.py file in entities/nodemodel/v2/primitives/. After processing all classes, it regenerates primitives/__init__.py with imports and the PRIMITIVE_NODE_WRAPPERS dictionary, and writes a comprehensive test file at test/tests/03_entities/nodemodel_v2_primitives_test.py with one test per primitive type.

This operator must be run inside Blender (not headless) because it needs live Blender shader node classes to be present for introspection.

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Further reading

• UI Layer overview
• Meta classes — Abstract_Panel, MpfbOperator, MpfbContext, pollstrategy