If you see a ton of official patches and tools in the latest file uploads list, that would be me archiving all the good stuff developers have been giving us over the years, with the staff's blessing. This was mostly a dump of files made to fill the gap in GameFront's library before it was relaunched as its own thing in 2018.
Latest version of the official Mod SDK for Command & Conquer 3: Tiberium Wars. Requires patch 1.07 or newer.
Tip: to run the Tiberium Wars Control Center with any release of the game, run it with the -ui parameter to load it. The Game Browser menu will list all properly installed mods.
Old GameFront description:
Here is the Mod SDK for C&C 3. Released finally! With this release, you will be able to modify C&C3 units, add your own, change the UI to your liking and plenty more!
Please note that you may need to download some more pieces.
C&C3 Patch 1.07 -- Required for everything.
NET Framework v2.0 Required to run the BinaryAssetBuilder application.
Visual C++ 2005 SP1 Required to run the BinaryAssetBuilder application.
ANTLR v2.77 Required when using the tag.
Mvp.xml v2.0 Required when using xi:include statements.
To get these, view the html readme included with the file. In addition, there are sample content packs which are useful to see how EA made the game: Worldbuilder, Unit Portrait Images, All UI Textures, Sample Unit Models.