C++ , Python, and math skills. From there you should be able to create your own apps, or get to learning the API for larger programs (3DSMax/Maya/etc.) to create tools specifically for them. And yes, you'll need to know the creation process/pipelines for 3D art if you want to create tools to help 3D artists. Also:…
Skills wise you will want Python and C++, if you know those you can easily learn other things like maxscript or C# if needed for certain studios. Also you dont need to be a good artists, but you must understand the whole workflow the artists follows, so you can build tools and improve the pipeline. Also depending on the…