Hi Virginia, Another thing to note is that in the target field, the path to the Chimera executable is embedded in double quotes (e.g. it is something like: "C:\....\chimera.exe"). To add the --stereo option, you need to add it outside the ending double quote and separated by a space, like this: "C:\...\chimera.exe" --stereo . Eric Pettersen UCSF Computer Graphics Lab pett@cgl.ucsf.edu http://www.cgl.ucsf.edu