It was the same thing for me basically. I moved from Wings3D+Bryce to C4D. Some of my old Bryce images (like this one from 2003 - http://www.renderosity.com/viewed.ez?galleryid=559973) took 40 hours to render. Not because of soft shadows or any advanced setting but because of the ligth setup (using light a dome). I've taken a look in the gallery and the stuff you have there doesn't look to be 4+ hour rendering material. Just basic light that probably will take Bryce a couple of minutes to render. If you discover a geometry error after 4 hours of rendering then you technique needs to be polished. Even with high end apps you need to check for stuff like that before you enable all kinds of rendering options.

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