FSX FSX Legacy Flatten

Hi. I have the original version of FSX with no SDK. Seems like every flatten software requires SDK. Is there any tool I can use to flatten scenery in the original FSX version?

Tools that create a flatten are relying on a compiler that is included in the SDK. MS decided to charge for the FSX SDK. If the tool maker shipped a copy of the compiler with the tool he would be violating MS's copyright. If you look around on the internet you should be able to find a copy of the FSX gold edition, which contains the SDK, for a reasonable price.