diff --git a/modelbuilder.py b/modelbuilder.py
index dd405d3..f0381a5 100644
--- a/modelbuilder.py
+++ b/modelbuilder.py
@@ -19,6 +19,8 @@ from modeller import ModellerError
 import pymol
 from typing import Dict
 from Bio.SeqRecord import SeqRecord
+from concurrent.futures import ProcessPoolExecutor
+from functools import partial
 
 @dataclass
 class PDBAlign:
@@ -34,7 +36,7 @@ class PDBAlign:
         self.pymol_instance = pymol.cmd
         self.pymol_instance.reinitialize()
 
-    def align(self):
+    def align(self) -> str:
         self.pymol_instance.reinitialize()
         # 首先，加载模板结构
         self.pymol_instance.load(self.template_file.as_posix(), "template")
@@ -44,6 +46,9 @@ class PDBAlign:
         self.pymol_instance.align("target", "template")
 
         return self.pymol_instance.get_pdbstr('target')
+    
+    def save(self, out_file: Path):
+        self.pymol_instance.save(out_file.as_posix(), "target")
 
 @dataclass
 class LoopModelBuilder:
@@ -124,16 +129,21 @@ class LoopModelBuilder:
         if not self.missing_info:
             self.logger.info(f'No missing residues found in {self.pdb_file}. Skipping model_missing_loops.')
             return mc_dict
-        for mc in self.missing_info:
-            out_file = f'{self.pdb_id}_{mc}.pdb'
-            self.analyzer_instance.split_chain(mc).to_pdb(out_file) # get misschain pdb file
+        self.logger.info(f'Missing residues info for {self.pdb_file}:\n {self.missing_info}')
+        # create workdir
+        for mc in self.missing_info.keys():
+            self.logger.info(f'Building model for chain {mc}')
+            workdir = self.pdb_file.parent.joinpath(f'./{self.pdb_id}modellerfix_{mc}')
+            workdir.mkdir(exist_ok=True, parents=True)
             mc_fasta = self.analyzer_instance.find_most_similar(self.sequences[mc]) # get misschain fasta file
+            # write fasta file
             mc_fasta_record = SeqRecord(mc_fasta, id=f'{mc}', description=f'{self.pdb_id}|{mc}')
-            out_fasta_file = Path(f'{self.analyzer_instance.pid}_{mc}.fasta')
+            out_fasta_file = workdir.joinpath(f'{self.analyzer_instance.pid}_{mc}.fasta')
             self.analyzer_instance.write_seq_to_fasta_single_line(mc_fasta_record, out_fasta_file)
-            self.logger.info(f'>{self.pdb_id}|{mc}|{self.missing_info[mc]}|{len(mc_fasta)}')
+            self.logger.info(f'>{self.pdb_id}|{mc}|missing site:{self.missing_info[mc]}|length:{len(mc_fasta)}')
             self.logger.info(mc_fasta)
-            modeller = PDBModeler(self.pdb_file, out_fasta_file, Path(f'./{self.pdb_id}modellerfix_{mc}'), mc, buildnumber, typestr)
+            # build model
+            modeller = PDBModeler(self.pdb_file, out_fasta_file, workdir, mc, buildnumber, typestr)
             try:
                 modeller_results = modeller.make_model()
             except ModellerError as mod_err:
@@ -147,23 +157,29 @@ class LoopModelBuilder:
             self.logger.info(f'Model files: {[file.name for file in modeller_results]}')
             # change id to original
             for i in modeller_results:
-                manalyzer = PDBAnalyzer(i)
-                manalyzer.change_chain_identifier('A', mc, split=False).to_pdb(i)
+                self.change_chain_identifier(i, 'A', mc, split=False)
+            # use pymol to align and merge
             if len(modeller_results) == 1:
                 # use pymol to align
-                aligner = PDBAlign(self.pdb_file, modeller_results[0],Path(f'{self.analyzer_instance.pid}_merge_model.pdb'))
+                aligner = PDBAlign(self.pdb_file, modeller_results[0])
                 pdbstr = aligner.align()
-                mc_dict[mc] = pdbstr
-                return mc_dict
+                mc_dict.update({mc: pdbstr})
             else:
                 self.logger.warning('more than one model file, please set num_loop to 1')
         return mc_dict
-            
-    def run(self, typestr:str = 'refine.very_fast'):
+    
+    @staticmethod
+    def change_chain_identifier(pdb_file: Path, chain_id:str, new_chain_id:str, split:bool = True) -> Path:
+        o = PDBAnalyzer(pdb_file)
+        o.change_chain_identifier(chain_id, new_chain_id, split=split).to_pdb(pdb_file)
+        return pdb_file
+
+    def run(self, typestr:str = 'refine.very_fast', buildnumber: str = 1) -> Path:
         split_dict = self.split_all_chains()
-        mc_dict = self.model_missing_loops(typestr=typestr)
+        mc_dict = self.model_missing_loops(typestr=typestr, buildnumber=buildnumber)
         split_dict.update(mc_dict)  # 更新 split_dict
-        self.import_and_merge_pdb_strings(split_dict, "merged_object", self.output_dir.joinpath(f'{self.analyzer_instance.pid}.modellerfix.pdb').as_posix())
+        out_file = self.output_dir.joinpath(f'{self.analyzer_instance.pid}.modellerfix.pdb')
+        self.import_and_merge_pdb_strings(split_dict, "merged_object", out_file.as_posix())
 
     def import_and_merge_pdb_strings(self, pdb_strings, merged_object_name, output_file):
         # 使用 PyMOL 实例导入和合并 PDB