Hi Mike, you can also easily get z-fighting artifacts without multi-threading as well, it would just previously happen on overlapping surfaces before and not so much on curves.

In prior versions before multi-threading I'm sure you've probably seen this kind of thing with 2 objects overlapping each other and one of them selected or colored differently than the other:



That's z-fighting right there, without any multithreading needed. Multithreading just throws some extra spice into the mixture, particularly with curves.

Basically z-fighting is a display artifact but one that's a normal part of video card display technology. It is possible to do some things to control it, mostly by having the software automatically pull things forward by a little bit in z to influence the result. But it's a somewhat touchy thing because if you pull forward by too much it then can make things show that you really wanted to have hidden.

- Michael