Like for example I made a simple sphere, yet after rendering you don't see it as a "perfect" round sphere, you can see it's kind of polygonal. Is there any way to fix this? Attached is a sample. The output picture was saved at the 100 quality setting.

it's called 'faceting' (or at least thats what I call it :-) & is a direct result of the number of polygons used in an object. The more polygons you add to a model the smoother the appearance but there is a corresponding increase in file size The attached screen cap from lightwave is an extreme example but will illustrate the problem all modellers have in balancing poly count with file size. left= 17,664 polys 414K (about 2megs converted to obj) right= 288 polys (6.4K about 30K converted to obj)

oh & to answer your final question, no there really isn't anyway to 'correct' it other than by increasing the polygon count of the model or perhaps smoothing the object in postwork.

The best way to approach this problem is to ask yourself if the item in this case the sphere a foregroundhero element of the final picture? If it isnt then you can prolly get away with a low poly count mesh and either by its size or by post work hide the spheres straight edges. If it is then keep increasing the polys to the point where it starts to appear rounded.

Another factor is the way the material is set. Most 3d programs allow you to control something called "surface smoothing." In Lightwave it's in the surfaces panel. Bryce has a control for it, too. Poser 4 appears to automatically apply it - there's no control, but I suspect Poser 5 will have it.

Anyway, it "smooths" surfaces (rounds them out essentially) based on the angle between polygons.

It's still better to have your "hero" elements more detailed (higher poly counts) and especially have your background elements with a lower count.