How to prevent 3d-tiles tileset disappearance when zooming out

Cesium for Unity
1

My use case:
Open 2 tilesets, one on a large area - not detailed and the second smaller and much more detailed.
I then clipp (using Clipping Tilesets – Cesium) the detailed tileset bounds from the first tileset to prevent the tilesets from overlapping in some places
when zooming out the detailed tileset disappears and leaves a “hole” in the first tileset

Questions

  1. How can I identify in code (event?) that a tileset disappears from the cesium map?
  2. Is there a way to prevent in-code the disappearance of a tileset when zooming out?

Thanks!

2

Hi @asaf.masa, welcome to the community!

Could you provide screenshots or a video of this behavior? It’s hard to tell what’s going on from a text description, so I’m not sure if this is expected behavior. It would also help to know whether you’re using Cesium-provided assets or your own data.

I’ll answer your two questions anyway:

  1. Unfortunately there is no event. :frowning: But you’re welcome to modify the plugin’s source code to implement one.
  2. You could decrease the Maximum Screen Space Error for a tileset. That will prompt higher levels-of-detail load in, and all levels should stick around for longer.
3

The 3D Tiles spec uses a property called “geometricError.” This value helps decide whether a tile should be shown or not, based on how far away you are from it.

First, try changing the Maximum Screen Space Error as mentioned.

Until you provide more details as requested, I can make some assumptions and try to help you:

(Assuming you’re using your own data and have access to the tileset.json file)

I think the high-detail tile is being shown up to a certain distance because the tile’s geometricError value works for that range. But if you go farther away, the tile won’t show up anymore, assuming you don’t have other tiles in the hierarchy. You can control this distance by changing the geometricError value in the tileset.json file. Try setting it to a higher number for the tile(s) you’re working with.

For an example, check out this JSON file: Montreal 3D Tiles. It has a tile-hierarchy, and the top-level tiles have a geometricError of 99999999, which is high enough to make it shown as the last resort in case none of the other more-detailed tiles are chosen.

1 Like
4

@yunusyurtturk @janine Thanks i will try to set the Maximum Screen Space Error and check the affects