I don’t know what it calls, the area has a gap, how to fix that?
You’re going to need to give us a lot more information. What tileset are you visualizing? How was it created? How can we reproduce this problem that you’re seeing?
Also, were those screenshots taken during loading, and the cracks eventually go away? Or had loading already finished?
I visualized a photogrammetry tileset, it was made from an unreal QuickStart tutorial, and that screenshot was taken after loading was complete, but the screen looks like it has gap areas, how do I merge the areas?
Which photogrammetry tileset? Which tutorial? I can’t suggest solutions without knowing what the problem is, and the problem is more than likely with the tileset you’re using, not with Cesium for Unreal. But I can’t be sure until I can reproduce the problem you’re seeing.