Attached Link: http://fartur.free.fr/galerie/tutorial/qtvr-tutorial.html

This is advanced because I am not gonna explain much: Make 6 faces by following the above tutorial link. Then add in masked objects to the faces using photoshop or equivalent. Convert to an equirectangular map using hdrshop (debevec.org/HDRShop) Then back in photoshop blur that image. Now use it in bryce as a simulated hdri. So you can add-delte any objects you want without worrying about poly count!