[UE5] Limiting WebTileRasterOverlay Request Bounds to a Specific WMTS Sub-region (Fixed TileMatrix)

Cesium for Unreal
1

Hi Cesium Team and Community,

I am currently using CesiumWebTileRasterOverlay in Unreal Engine to load a custom WMTS service that generates heatmap data.

The Problem:
My WMTS service has specific constraints:

  1. The valid data only exists at TileMatrix level 7.
  2. The valid geographic extent is very limited, specifically within these tile coordinates:
    • TileCol: [209, 215]
    • TileRow: [36, 39]

Currently, when I add the overlay, Cesium attempts to request tiles based on the camera’s view and standard quadtree splitting. This results in two issues:

  • It requests tiles outside my valid range (which are empty or invalid).
  • It only shows a small fragment of the heatmap because it doesn’t seem to “lock” onto this specific small region effectively at the correct zoom level.

My Goal:
I want to configure the WebTileRasterOverlay (or use a specific material/logic) such that:

  1. Regardless of where the camera moves, the overlay focuses on displaying this specific rectangular region defined by the TileCol/TileRow bounds above.
  2. It forces the request to use TileMatrix 7 (or scales appropriately from it) so the heatmap covers the intended area completely, rather than trying to fetch global tiles.

Is there a way to set a custom bounding box or tile range limit for a WebTileRasterOverlay? Or should I be modifying the URL template to enforce these parameters?

Any advice on how to clamp the overlay to this specific sub-region would be greatly appreciated.

Thanks!