The only place where there may be catagory limits is in an art competition. Somebody using Poser out-of-the-box work/render may be at a disadvange against a Poser, Maya, Max, Vue, Bryce, Lightwave, Photoshop, Painter, work/render, etc. combination. So maybe you have a out-of-the-box catagory, and maybe a 'freestyle' catagory. Sorta like a 'mixed media' catagory in natural media. Just thinking aloud.