Yes you can.
Of course you need to use it in the standard OBIEE way: define it in your RPD physical layer, model it in a business model and expose it to users in a subject area.
PS: I really hope nobody will suggest to do a direct database request as this is not really "BI Answers" anymore! Use SQL Developer: same result for free ...
You should be able to include a materialized view in the physical layer of the RPD, which would treat it simply as another table (the RPD would not care that it is a view, materialized or not). You could then join to other tables, and map logical columns as normal.
Thank you all for the quick response.