Dear Sir/Madam, I am Dung. I am currently using Chimera to do the refinement for my protein because it has some large missing residues segments. I use Tools/ Loops- Model refinement of Chimera software to do that task. As it was failed to generate models if I performed refinements for all missing residues segments. Thus, I decided to refine them not at once. The problem is that I could not find how to combine the separated loops from models after refinement. I am new to Chimera so I hope that my description can be useful for you to imagine my problem. I hope that you could support me to solve this problem. I really appreciate it. Thank you for spending your valuable time. Yours sincerely, Dung Hồ Ngọc Phương Dung International University - Vietnam National University Email: phuongdunghongoc@gmail.com