Hello I've been studying PPCHTEX these days, it's very powerful, and I cannot control it well. I just wrote a chemical struture like: ================================ \startchemical [size=small,scale=small,width=fit,height=fit,frame=on] \chemical[SIX,SB13456,DB2,Z] [C,C,C,C,C,C] \chemical[PB:Z1,ONE,Z0,SB18,Z8,MOV1,ONE,DB1,SB7,Z07,MOV1,ONE,SB13,Z03,MOV1,ONE,SB1,DB7,Z017,PE] [C,H,C,H,C,H,C,CH_3,O] \chemical[PB:Z2,ONE,Z0,SB1,Z1,PE] [C,CH_3] \chemical[PB:Z3,ONE,Z0,SB3,Z3,PE] [C,H] \chemical[PB:Z4,ONE,Z0,SB45,Z45,PE] [C,H,H] \chemical[PB:Z5,ONE,Z0,SB56,Z56,PE] [C,CH_3,H] \chemical[PB:Z6,SIX,Z3,SB23,Z24,PE] [C,CH_3,CH_3] \stopchemical ================================ only the carbon-ring is in the frame, I think maybe PB:..,PE pair does not change the size of the picture. I know I can use like ================================ \startchemical [size=small,scale=small,width=9000,height=5000,left=3000] ================================ to specify the size, but I need to try several times to get a correct version. Is there any parameter that do this staff automatically? Thanks -- Sincerely yours, Chen ---------------------------------------------------------------- Zhi-chu Chen | Shanghai Synchrotron Radiation Facility No. 2019 | Jialuo Rd. | Jiading | Shanghai | P.R. China tel: 086 21 5955 3405 | zhichu.chen.googlepages.com | www.sinap.ac.cn ----------------------------------------------------------------