you can play with dds as long as you want and change that in db. (all you can do)
As for the 3d graphic that involve on rappelz the base format is (.scn/scene file for xsi/softimage). To create a new design/edit an existing one first it need to decrypt the nx3,cob,naf to get their proprieties and based on that to create an export plugin for xsi.
You need the full proprieties on nx3,naf,cob,dds(all4 make the graphic part) so the game to render well the new design.
To create new design,animation is impossible for now, until some1 will decrypt those files.
+ even if some1 will succes who will be the one to recreate the scn. it will require to get the full scn files from kor company so we can edit anny design or at least the 3 plugins that they use to export the scn in that 4 formats.
Ah you changed thedds content with your desire one..ok if u fit well..is rendered..but well...isan static immage, no motion, it require new animation(cob) based on that design. too bad you need to break an kor company to get 3 plugins
Now you have 2 options:
1. let it be and thats it.
2.break the encrypt of the nx3,cob,naf
remember to edit the graphic of rappelz is like you have an jpg super edited with effects but to add more you need the psd with all layers and that means youll need to take it from the scratch,unless you get somehow the psd one/in our case scn files.
hope i make myself understanded.