Previously, 3ds Max SDK .vcproj files included libraries as just another source file, using a relative path. This prevented building Win32 and x64 binaries in the same folder. During the project file conversion, LIB files were removed form the list of 'source files', and moved as 'additional linker dependencies' in the project settings. The relative paths were added to the linker options, with appropriate modifications for the x64 builds.

Most projects thus have the maxsdk\[x64\lib and maxsdk\[x64\lib folders already in their project settings, and adding a new library file is just a matter of adding it to the 'linker settings'. When you add a .lib, it should be added to all relevant configurations and platforms.

Most importantly, you can do 32- and 64-bit builds in the same folder.