I would like to use my obj format file instead of using images from a camera to create object targets, is that possible?
At the moment this is not possible with the SDK. Currently what you could do, is to work with images that are exported out of a 3D program. So you'd need to render images including the textures, that you then use to upoload in Studio for the .wto file.
We'll add to your list of interested parties for such a feature and keep you updated.