I’m new to the modelling tools.
Wanted to know, whether we can view/edit the Er digrams created from the toad modeler on ERWIN .
IS there any big restriction between these two tools.
Hello,
I don’t think you can view ERD created in TDM in ERwin. However, you can ask ERwin support. 
Regarding TDM, import of ERwin 7.1 XML files of Oracle 10g and Oracle 9i database is supported. It’s not an officially supported feature, it’s supported only via the community from where you have to download appropriate packages. Please see:
http://modeling.inside.quest.com/entry.jspa?externalID=2411&categoryID=34
Note: Instructions in PDF doc are included.
If you have more questions, please write me back. Thanks.
Regards,
Vladka + TDM Team
Why don’t you create DDL with ER WIN and then reverse engineer with TDM?