What is this showing

[Aussie]

This pattern moves as you move the 3D preview

[Tailmaker]

I had that on a file and Vectric acknowledged something to be fixed. I have not gone back to check if they did in newer versions.

But it showed only, when turning a 2-sided preview with the mouse looking at the back of the active side and vanished when zooming in. So, for me it was not a big deal. Just swap the active side to look at the back and it does not show.

[Tex_Lawrence]

That could be called an “easter egg” in programming circles; something a silly programmer adds without permission and only shows up during certain situations.

Vectric would probably be reluctant to admit such a thing, and they might have some trouble locating it.

[Aussie]

Thanks guys

[adze_cnc]

In the options try changing to the software renderer and see if it goes away.