It looks like Qt Design Studio is a commercial product that's free for evaluation only. > Qt Design Studio is available today as a free tool for everyone to tr

It looks like Qt Design Studio is a commercial product that's free for evaluation only. > Qt Design Studio is available today as a free tool for everyone to try out and evaluate. You will need a commercial Qt developer license to distribute your UIs created with Qt Design Studio. > We are also working on an open source version with a limited feature set, to be published in December. The Qt library itself has both commercial and LGPL licenses. You can safely use LGPL libraries in commercial products with a couple obscure provisions: it's commonly held the library has to be dynamically linked, the user has the right to replace the Qt dynamic libraries, and maybe a few other inconsequential things.