ya you guys are right. i havent realy done any modding accept some custom characters i used nif and blender 2 make. and i don't know how to make landmasses or custom creatures.and is it against eula 2 use any other meshes and textures from any other games
Yes, it is against the EULA to use any resources like models and textures straight from another game. That's not to say you can't use
ideas from other media to make a mod, since it's non-profit, however, even that can get into some intellectual property issues which are often debated about when mods are based on large and successful franchises like Star Wars, Halo, etc.
If a mod like this was made, it would probably be best not to call it "Clash of the Titans: the 3D movie mod". I doubt Ray Harryhausen would mind, but modern Hollywood franchises tend to be money grubbing bastards with no regard for creativity or artistic value.
What you really should do, if you want to make a mod like this, is go see the original
Clash of the Titans, and make a mod based on that.