Hi I have to ask the same question again. #define ga_24 120 505 ; H - N - CH3. H, HC-6-ring, H-NT-CHn 90 I confuse with the comma "," and " - " does it mean ? =>H - N - CH3 ( the angle between H - N - CH3, right?) H - N - H, H - N - (HC-6-ring) H - N - CHn 90 (HC-6-ring) - NT -CHn CH3 - NT - CHn 90 Thank you Lin