Does it have anything to do with meshing angle?

No, it has to do with very large objects and very small objects in the same view. The mesher has to choose one. Hiding and unhiding clears up needed objects though....

Hi milkywaif,

> Is this some kind of a bug or limitation of MoI display engine or is it my graphic card performing not good (Quadro 4000)?

It's a limitation in MoI's display engine, it doesn't really have anything to do with your specific card.

It has to do with edges being drawn right over the same area as the surfaces - in order for the edges to not be kind of submerged into the surface (which is what is causing the artifact you see there) they have to be pulled forward in depth. It's kind of difficult to choose how much to pull them though, if you pull too much then things that are supposed to be hidden are displayed and if you pull too little things get hidden when they're supposed to be shown.

The way the depth buffer on video cards work in general, there is also less depth resolution available if you have stuff right up next to the eye point. That might be what's actually most responsible for your particular case here, not just the size of the bigger object but that it's probably running back behind the eye point.

But it's just a display artifact and doesn't mean anything is wrong with your objects or indicate any actual problem at all, you should just ignore it.

It's unfortunately not very feasible to try and get pixel perfect results in the MoI viewport window because it's very focused on trying to show things quickly. Trying to clear this particular artifact up would involve doing more work right during the middle of the display calculation.

You might find that it could be reduced if you switch your 3D view to a parallel projection instead of perspective projection. Or like you already found when you want to work on small objects hide the big ones. One quick method for doing that is to select your small object and then right click the Edit > Hide button. That will do an "isolate" where everything else other than the selected object is hidden. It will also remember what things were visible before doing the isolate and when you right-click on it a second time it will restore the previous hidden/visible state.

- Michael

Michael, thanks for the explanation.

> It's unfortunately not very feasible to try and get pixel perfect results in the MoI viewport window because it's very focused on trying to show things quickly. Trying to clear this particular artifact up would involve doing more work right during the middle of the display calculation.

When I boolean>union two objects, artifact is gone. So does that mean largest object has some kind of accurate drawing priority over smaller objects in the scene?

Hi milkywaif, the zbias amount (amount of pull forward), is set on an individual object basis based on its bounding box size. So the small object has a smaller zbias pull associated with it, once it's booleaned those edges will then use the zbias amount based on the bounding box of the whole large object.

In your particular case there it needs a higher amount of zbias for the display artifact to go away. But unfortunately just increasing zbias up for everything instead causes a different artifact where stuff that's supposed to be hidden will bleed through.

- Michael