When upgrade from legacy tilesets, 1.0 and 1.1 have different result and all of them lost some tileset details

[snowwindsand]

I have a legacy tileset file. When I load it in the old Cesium version (1.75), it looks like this.

When I upgrade it to version 1.0 using the tool, command is 3d-tiles-tools upgrade -i ./tileset.json -o ./upgrade
it appears like this

there's an issue with the model's orientation, and the detail in the top-left corner becomes worse.

When I upgrade it to version 1.1 using the tool, command is 3d-tiles-tools upgrade -i ./tileset.json -o ./upgrade --targetVersion 1.1
it looks like this

the model's orientation is correct, but the detail in the top-left corner remains poor.
Can anyone tell me how to preserve the detail in the top-left corner? What parameters should I adjust?

[javagl]

There are different aspects that are considered to be "legacy". The upgrade is a best-effort attempt to make sense of certain kinds of legacy data. There might be something very specific in that tileset that is not anticipated during the upgrade, and that may explain the differences.

At a glance, the output from upgrading to 1.1 looks somewhat reasonable. When you mention the "details in the top-left corner", does this refer to this thingy here:

?

If so, it might be good to know whether this becomes visible when you zoom closer. Then it might be an LOD issue. If that data contains I3DM, then some of this may also be affected by CesiumGS/cesium#12108

Based on the screenshots, I can hardly make more than guesses. If the tileset has a "reasonable size", then sharing it (either by attaching it as a ZIP here, or via some (private) upload or via mail) could help investigating this further.

[snowwindsand]

@javagl thank you for your reply. Sorry, my mistake. the top-left part is this section. As shown belower:
original version:

upgraded version:

The upgraded version appears more jagged and less detailed compared to the original, with noticeable loss of smoothness. The geometry looks more angular and coarse. Do you know how to preserve the original level of detail or which parameters need adjustment to fix this?

[javagl]

It's hard to say anything for sure from the screenshot alone.

But an important point is: The 3D Tiles Tools upgrade command does not modify the geometry data. The geometry in the output should be exactly the same as the geometry in the input. But the first screenshot of the first post (the original one, in Cesium 1.75) looks like it might use "unlit" rendering. This could explain a different visual appearance: In the "old" version, you just could not see the "jagged" shape of the geometry, because it looked all flat. With the upgraded data (which is no longer using "unlit" rendering by default), the normal- and lighting computations may cause it to appear more "jagged" or "rough".

You could try setting

tileset.customShader: new Cesium.CustomShader({
  lightingModel: Cesium.LightingModel.UNLIT,
});

for the upgraded tileset, and see wheher the result is closer to what you expect.

[snowwindsand]

It's hard to say anything for sure from the screenshot alone.

But an important point is: The 3D Tiles Tools upgrade command does not modify the geometry data. The geometry in the output should be exactly the same as the geometry in the input. But the first screenshot of the first post (the original one, in Cesium 1.75) looks like it might use "unlit" rendering. This could explain a different visual appearance: In the "old" version, you just could not see the "jagged" shape of the geometry, because it looked all flat. With the upgraded data (which is no longer using "unlit" rendering by default), the normal- and lighting computations may cause it to appear more "jagged" or "rough".

You could try setting

tileset.customShader: new Cesium.CustomShader({
lightingModel: Cesium.LightingModel.UNLIT,
});
for the upgraded tileset, and see wheher the result is closer to what you expect.

Thank you for your response. I'll try it out and see how it works.