When I add multiple imageryLayers to 3dtiles, there is a warning: ‘Draped imagery requires 12 texture units, truncating’

CesiumJS
1

My imageryLayer sometimes doesn’t render completely, leaving a missing section in some areas

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Hi @Cloud_6 ,

Thanks for posting and for being a part of the Cesium community. Could you possibly provide us sample code using our sandcastle tool https://sandcastle.cesium.com/ to reproduce the error your are seeing? This will help us more quickly understand the specific problem you are facing.

I am not sure we support your use case, but sample code will help us clarify that answer.

Thanks!
Luke

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This is a limitation of the current implementation for draping imagery on 3D Tiles. It is “tracked” as part of Follow-ups for draping imagery on 3D Tiles · Issue #12643 · CesiumGS/cesium · GitHub (where it is summarized under Point 3, “Upsampling is not implemented”).

When using a single imagery layer, then this should never not happen: The approach right now is to try to pick an imagery level so that each primitive is covered by ~“roughly one” imagery, which should mean that it should require not more than 4 imageries (with up to 9 being a very theoretical upper limit).

But when multiple imagery layers are used, then the texture unit limit of the GPU can be exceeded by that. There might be approaches to allow maybe 2 layers (with lower resolution). But it can only really scale to multiple layers with proper upsampling.