I also think that way of inheriting properties from mental ray "exclusive" options (Like aproximation editor, or Shadow options in light properties.) is not the best way how to integrate new render engines into XSI. It could be helpful for beginners, but it could pose some restrictions for users that are already used for example to renderman compliant terminology. I would prefer to have option to have multiple properties or shader trees for different renderers hooked on one object. In this way I could follow the mr-way of doing things and for different passes or element use another renderer without modifying the same options. Actually this is the way Affogato works and how 3Delight is integrated to Maya (except for shader networks). I do agree that for example Softimage base library should be supported and translated, but for other shaders it should be always prefered (in my opinion) to not to try emulate options of mr because the mechanics and results differ. (AO in 3Delight for example).
Francesco.
