Hi, Here is a question raised by a colleague on the ccp4 bulletin board. Since Chimera was mentioned in his post I thought you guys might have an answer to his question (positive or negative), hence I'm posting his message here. Cheers, Boaz Hello, I am working on a protein whose EM model has been built long time ago. The crystal structure has been solved recently and I want to know the difference between the crystal structure and EM model. Unfortunately there is no data in the EM data base, so I can not use Chimera or Phaser to fit the crystal structure into the EM electron density directly. My friend downloaded the VRML file of the EM model ,which can be viewed using Cosmo player. And I can make VRML file from my crystal structure using Pymol or Chimera. My questions is: can I superpose two VRML files which come from EM and crystal models? If so, how can I do that? Thanks in advance! Best wishes leo Boaz Shaanan, Ph.D. Dept. of Life Sciences Ben-Gurion University of the Negev Beer-Sheva 84105 Israel Phone: 972-8-647-2220 ; Fax: 646-1710 Skype: boaz.shaanan