Hi Leonard, that's basically a display artifact that you kind of learn to ignore.

In order to display the model on the screen, it has to be diced up into triangles to be sent over to your video card.

That's because your video card display hardware really only knows how to draw triangles, it does not itself know how to draw full smooth surface patches like your model actually contains.

So what you see shaded on the screen is only an approximation of your actual model data.

If it does not get approximated with enough density, it will result in the display you see there.

But that is not necessarily a bad thing, it can help in some situations to have a kind of rougher display since that makes for fewer triangles to be sent to the video card. If you get a whole lot of triangles it can tend to slow things down.

And in fact, it looks like you have reduced your settings from the default at some point in order to make for a coarser (and therefore faster) display at some point - by default the angle is 10 degrees and "add detail to inflections" is on. But even with the default settings which are somewhat on the dense side, you can still sometimes see evidence of the triangulation process.

Just be aware that seeing that does not automatically indicate that there is an "error" or in your model, what you are seeing on the screen there is only an approximation of your actual model definition.

So basically you just learn to ignore what you are seeing there.

In the future I'll probably be making some adjustments to try and do a bit more strategic refinement of the display mesh, but it is a sensitive area for performance, since just slamming out a whole ton more triangles can easily lead to bogging things down.

- Michael