Just making sure everyone knows this existed, I didn't and I'm always checking in on the modding community, seems to me that they released this under the rug a while ago. I was wondering how they made Priboi story!
http://games.softpedia.com/progDownload/S.T.A.L.K.E.R-Shadow-of-Chernobyl-X-Ray-SDK-Download-16207.html
And this is a model converter made by a man in the STALKER mod community. It will convert any stalker model to .object, a friendly format for many model programs like 3Ds Max and Maya.
http://chernobyl.extra.hu/converter_by_bardak.zip