www.kraytracing.com

object and scena

First, prepare yours sample scenes so it could be opened easily on remote computer. Some people wouldn't bother if they couldn't open a scene right away.

In General tab change "Pixel order" say to "Scanline" instead of "Progressive" and you will get better result right away
To improve things you will have to adjust your FG settings, there is screenshot with FG setting used for my test render.
Essentially, "Angular tolerance" controls number of FG samples on curves surfaces. Less angle - more samples. This way artifacts get smaller and maybe can be considered as real world imperfections. If you want to get really smooth surface - you have to use 2 passes FG. A bit slower render time and don't fit animation well (because of huge cache files).
If anyone have better ideas would be interesting to hear, especially for 1 pass FG

what he said! ^^^^ Good job Leftover. Not much else I can add here.

Leftover wrote:In General tab change "Pixel order" say to "Scanline" instead of "Progressive" and you will get better result right away

That just changes the preview doesn't it, not the render itself, or does it? I'd be interested to know how this improves rendering (other than more accurate 'time left' prediction).

It doesn't affect "raytrace" part but it does affect how FG samples are placed. In this case "Progressive" mode produces more aligned FG sample placement which causes distinctive vertical artifacts. I guess it was only reason to make all these modes.

Leftover wrote:It doesn't affect "raytrace" part but it does affect how FG samples are placed. In this case "Progressive" mode produces more aligned FG sample placement which causes distinctive vertical artifacts. I guess it was only reason to make all these modes.

Yes that is correct. It does affect placement of samples. I usualy work with scanline or random mode. Those are the the fastest also. The renderworm and frost are good too.