Presence of University expansion pack is necessary
IMPORTANT:The fireplace is a new separate object and it works as a fireplace should.You will find the fireplace in the Buy mode in the Appliances section,this solution has some side effects,read here.A big thanks to Numenor at Mod The Sims 2 for helping me with the fireplace.The curtains is original object,work on straight and diagonal walls . Some of the objects are put together as shown in the pictures using codes:moveobjects on/off and boolProp snapObjectsToGrid false/true
All objects are tested in game and they are compatible.
Download it here: