I am planing to use sass/compass in a big project. is it possible that some team members can use simple css while others can still write scss?
what i exactly wants to know is the way compass/sass listen to scss and convert css the same moment can it also listen css file and convert back any changes in scss file ?
I'd say no — or at least, not easily. SCSS is fully compatible with regular CSS, and it does compile to CSS, but not the other way around, so the source file should be either CSS or SCSS.
Still, it depends on your project. Say two members are working on two completely separate parts of the projects. They can use separate files, and choose to work in either SCSS or CSS. Their files may then be included in a main SCSS file or otherwise be merged together with a build script — or be kept separate in production, even. That wouldn't be any problem.
Still, I'd always prefer all the team members to work in a similar way, so that they can easilly cover each other when there's a problem.