weird lighting problems

Hi guys!

First post here, so please be gentle. I’m just trying to get into Blender (or 3D in general, for that matter) and I’m currently trying to create a testing environment for me to put some models in and do some animation testing and have my work nicely showcased. For this I’m trying to emulate the kind of environment that can be seen in the chicken chair short movie.

So far, all I’m getting is this:
http://img92.imageshack.us/img92/7748/testroom7ge.jpg

The scene setup is the following. A cube (normals facing inwards) is serving as the “room”. The material is set to shadeless grey. Since shadeless materials don’t receive shadows I have duplicated the cube, scaled it a tiny bit inwards and made it “shadow only”. I then added an arealight which basically covers the whole topside of the cube. This gives me some nice soft shadows. The image was rendered with 10 samples for the light, it looks much nicer with 16 samples but takes considerably longer so I will use that only for final renders.
I set the area light to “no specular” since the sphere looked overbright due to the huge specular of the area light. Instead I put a normal lamp right next to the center of the area light for some nicer highlights. I also tried to light it with an arealight from below to simulate some of the bouncing of the overhead light but that didn’t quite look right. This shot is rendered with some grey ambient light.
For some reason, it still doesn’t feel right. I’m not a fan of ambient light because it isn’t subject to occlusion (or is it?). It just doesn’t feel right. Ambient occlusion probably won’t work because there is no “sky” to bounce the rays off.
I tried using yafray with some GI stuff but Yafray doesn’t seem to support neither shadeless nor shadow-only materials. That and the chicken chair was supposedly rendered with the internal renderer.

And what really gets me is the fact that the sphere has a clearly polygonal look to it in certain places, although it’s set to smooth.

Any suggestions on what I could do differently?

Get rid of the cube. Use only a shadow only plane and ambient occlusion. Change the world color to grey to get the grey background you want.

Add subsurf (render level 2) to the sphere.

Yeah, just did that. I actually did remove the colored cube a short bit after posting this topic but it’s totally true that I don’t need a cube. A plane is just as fine and renders a bit quicker.
Subsurfing did the trick, btw. The sphere looks fine now.
BTW: what’s the lighting setup for your renault scenic? (Not the sunflow renders but the earlier ones)

This is what I got so far.
http://img521.imageshack.us/img521/7813/testroom26vt.jpg
I took out all of the lights exept for the upper arealight. It’s kindof ok but I’d rather build the impression that light is reflected by the (imaginary) floor and (possible) walls. Placing another (no-shadow, no-specular) arealight below the sphere just doesn’t look quite right. The light comes too clearly from below and even from areas where there should be shadow.
http://img52.imageshack.us/img52/7957/testroom30xc.jpg

Any other suggestions on how to light this environment?

For my Renault scenic I have a ground plane curved around the model (like a deep plate) that provides the reflections, a blended sky (white down, black up) and two area lights. The main one provides the shadows and the second one, near the camera, is the fill light.