SHAPE.area / length empty for sdo_geom data

hi,

I create a feature class from arccatalog using sdo_geom keyword. the feature class is created successfully and i can insert new data (via ArcMap by drawing it manually) and also i can view the data normally. But when I look into shape.area and shape .length they are empty...

Why ?

Database: oracle 10.2.0.3, arcsde 10.0