A free app for Windows, by Bethesda.

Are you in the market for an Elder Scrolls mod? Try Nexus Mods’ Official Oblivion Construction Set. Official Oblivion Construction Set is an unofficial app to use with The Elder Scrolls: Oblivion and is an essential tool to create, edit, and publish content for the game. The app includes a handy spell checker for catching typos. 

In order for you to use this mod, you’ll need a copy of Elder Scrolls IV: Oblivion, a DirectX 9.0c or any compatible graphics card, administrative rights, and at least 2GB RAM. RAM requirements may differ according to your needs. For example, you’ll need 1GB RAM if you want to build worlds and levels. Overall, Oblivion Construction Set is the perfect mod for creative gamers.