bex_export.py

import bpy
import bmesh
import os
from . bex_utils import *

class BatEx_Export:

  def __init__(self, context):
    self.__context = context
    
    self.__export_folder = context.scene.export_folder
    if self.__export_folder.startswith("//"):
      self.__export_folder = os.path.abspath(bpy.path.abspath(context.scene.export_folder))

    self.__center_transform = context.scene.center_transform
    self.__apply_transform = context.scene.apply_transform
    self.__one_material_id = context.scene.one_material_ID
    self.__export_objects = context.selected_objects
    self.__export_animations = context.scene.export_animations
    self.__mat_faces = {}
    self.__materials = []
  
  def do_center(self, obj):
    if self.__center_transform:
      loc = get_object_loc(obj)
      set_object_to_loc(obj, (0,0,0))
      return loc

    return None

  def remove_materials(self, obj):
    if obj.type == 'ARMATURE':
      return False

    mat_count = len(obj.data.materials)

    if mat_count > 1 and self.__one_material_id:

      # Save material ids for faces
      bpy.ops.object.mode_set(mode='EDIT')

      bm = bmesh.from_edit_mesh(obj.data)

      for face in bm.faces:
        self.__mat_faces[face.index] = face.material_index

      # Save and remove materials except the last one
      # so that we keep this as material id
      bpy.ops.object.mode_set(mode='OBJECT')
      self.__materials.clear()

      for idx in range(mat_count):
        self.__materials.append(obj.data.materials[0])
        if idx < mat_count - 1:
          obj.data.materials.pop(index=0)

      return True
    else:
      return False

  def restore_materials(self, obj):

    # Restore the materials for the object
    obj.data.materials.clear()

    for mat in self.__materials:
      obj.data.materials.append(mat)

    obj.data.update()

    # Reassign the material ids to the faces of the mesh
    bpy.ops.object.mode_set(mode='EDIT')

    bm = bmesh.from_edit_mesh(obj.data)

    for face in bm.faces:
        mat_index = self.__mat_faces[face.index]
        face.material_index = mat_index

    bmesh.update_edit_mesh(obj.data)

    bpy.ops.object.mode_set(mode='OBJECT')

  def do_export(self):

    bpy.ops.object.mode_set(mode='OBJECT')

    for obj in self.__export_objects:
      bpy.ops.object.select_all(action='DESELECT') 
      obj.select_set(state=True)

      # Center selected object
      old_pos = self.do_center(obj)

      # Select children if exist
      for child in get_children(obj):
        child.select_set(state=True)

      # Remove materials except the last one
      materials_removed = self.remove_materials(obj)

      ex_object_types = { 'MESH' }

      if(self.__export_animations):
        ex_object_types.add('ARMATURE')

      # Export the selected object as fbx
      bpy.ops.export_scene.fbx(check_existing=False,
      filepath=self.__export_folder + "/" + obj.name + ".fbx",
      filter_glob="*.fbx",
      use_selection=True,
      object_types=ex_object_types,
      bake_anim=self.__export_animations,
       bake_anim_use_all_bones=self.__export_animations,
      bake_anim_use_all_actions=self.__export_animations,
      use_armature_deform_only=True,
      bake_space_transform=self.__apply_transform,
      mesh_smooth_type=self.__context.scene.export_smoothing,
      add_leaf_bones=False,
      path_mode='ABSOLUTE')

      if materials_removed:
        self.restore_materials(obj)

      if old_pos is not None:
        set_object_to_loc(obj, old_pos)