i always thought it was calculating the patience of the person waiting, jk, :) like in the prev posts, trans,bump, shadow, and the more polys the longer the render because each surface"polygon" has those calculations done for it, raytracing adds reflection,refraction, and prob a few others, hence the longer render times, and i dont know if poser does,but a good renderer only renders whats in the cameras FOV, HTH's