preferences.py

import os
import sys
import bpy


class BrignetPrefs(bpy.types.AddonPreferences):
    bl_idname = __package__

    @staticmethod
    def append_modules():
        env_path = bpy.context.preferences.addons[__package__].preferences.modules_path

        if not os.path.isdir(env_path):
            return False

        lib_path = os.path.join(env_path, 'Lib')
        sitepackages = os.path.join(lib_path, 'site-packages')

        if not os.path.isdir(sitepackages):
            # not a python path, but the user might be still typing
            return False

        platformpath = os.path.join(sitepackages, sys.platform)
        platformlibs = os.path.join(platformpath, 'lib')

        mod_paths = [lib_path, sitepackages, platformpath, platformlibs]
        if sys.platform.startswith("win"):
            mod_paths.append(os.path.join(env_path, 'DLLs'))
            mod_paths.append(os.path.join(sitepackages, 'Pythonwin'))

        for mod_path in mod_paths:
            if not os.path.isdir(mod_path):
                # TODO: warning
                continue
            if mod_path not in sys.path:
                sys.path.append(mod_path)

        sys.path.append(env_path)
        return True

    @staticmethod
    def append_rignet():
        rignet_path = bpy.context.preferences.addons[__package__].preferences.rignet_path

        if not os.path.isdir(rignet_path):
            return False

        if not os.path.isdir(os.path.join(rignet_path, "utils")):
            # not the rignet path, but the user might still be typing
            return False

        if not rignet_path in sys.path:
            sys.path.append(rignet_path)

        return True

    def update_modules(self, context):
        self.append_modules()

    def update_rignet(self, context):
        self.append_rignet()

    modules_path: bpy.props.StringProperty(
        name='RigNet environment path',
        description='Path to Conda RignetEnvironment',
        subtype='DIR_PATH',
        update=update_modules
    )

    rignet_path: bpy.props.StringProperty(
        name='RigNet path',
        description='Path to RigNet code',
        subtype='DIR_PATH',
        default=os.path.join(os.path.dirname(__file__), 'RigNet'),
        update=update_rignet
    )

    model_path: bpy.props.StringProperty(
        name='Model path',
        description='Path to RigNet code',
        subtype='DIR_PATH',
        default=os.path.join(os.path.join(os.path.dirname(__file__)), 'RigNet', 'checkpoints')
    )

    def draw(self, context):
        layout = self.layout
        column = layout.column()
        box = column.box()

        # first stage
        col = box.column()
        row = col.row()
        row.prop(self, 'modules_path', text='Modules Path')
        row = col.row()
        row.prop(self, 'rignet_path', text='RigNet Path')
        row = col.row()
        row.prop(self, 'model_path', text='Model Path')

        row = layout.row()
        row.label(text="End of bRigNet Preferences")