Hi elaine, I've a few questions to ask about colouring surface by electrostatic potential and hydrophobicity: 1. I understand that I can use render by attribute to show surface hydrophobicity. But because it's a residue attribute, any surface of the same residue will be getting the same colour. Is there a way to calculate the surface hydrophobicity based on atoms in the vicinity instead of simply using the residue hydrophobicity values? 2. Because I have problem installing delphi, I have resorted to using the coulomb surface colouring tool. How different is this from the procedure of adding hydrogen, adding charge, then render by attribute ? Will I expect to see the same result ? Thanks elaine! Cheers, Sumitro Institute for Infocomm Research disclaimer: "This email is confidential and may be privileged. If you are not the intended recipient, please delete it and notify us immediately. Please do not copy or use it for any purpose, or disclose its contents to any other person. Thank you."