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 :)
Official Mod SDK for Command & Conquer: Red Alert 3.
The Installer for the MOD SDK currently includes these pieces:
3DS Max plugin
There are 2 sets of 3DS Max plugins included in this package. One requires that you have 3DS Max 9 and the other, 3DS Max 7 with service pack 1 or 3DS Max 8 installed.
Note that 3DS Max 9 was used for the development of Red Alert 3, and is therefore the most likely to function correctly. The 3DS Max 7 plugin was not used by the development team, but should still be fully functional.
To install, copy the contents of "3dsmax7_plugin" found in your MOD SDK folder into their respective folders in the "3dsmax7" install directory. Similarly, copy the contents of "3dsmax9_plugin" into the respective folders for 3dsmax9.
This will copy the actual plugin, several useful MaxScripts and shaders that can be used in Max to configure materials. See the 3DSMax section in the documentation for more info.
The W3XViewer can be launched from anywhere, and does not need to be copied. If you have all your art files (W3X files and textures) in one directory W3XView can find them all together; however, the game file structure layout is different:
Typically our artists create W3X files and textures for one unit or structure in a single directory, and then copy over the final files into the W3X and texture directories that the game needs.
EALAModStudio is the replacement for the Buildmod.bat functionality from the C&C 3 Mod SDK. It is used to compile your mod into a form the game can read, and deploy it to the proper directory. In addition, EALAModStudio has the capability for users to add functionality to the mod compilation process. See the EALAModStudio documentation in the main SDK documentation.
Additional documentation in HTML format can be found in the Documentation directory. This includes documents about the various parts of the 3DS Max plug-in, the W3XViewer and further art creation rules (eg. how to set up house coloring). There is also the sections detailing how the Sample MOD was created.
MOD to your hearts content,
EAMastermind and the EALA Command & Conquer Team