Currently the JavaScript Maps SDK doesn't support mixed Raster tiling sizes in 3D SceneViews.
Raster API tiles only work when all other layers have same tiling size. (link)
Since most maps created with the JavaScript Maps SDK use ESRI Basemaps, map creators or developers are often constrained to using layers with 256x256 tiling schemes.
This is unfortunate because increasingly applications are recommending 512x512 tiling schemes for better performance on large or high-resolution devices (example1, example2). Our own limited testing suggests improvements as well.
We would be interested to see SceneView support mixing 256x256 and 512x512 tiling schemes since both are pretty common.
Failing that, we would be interested to see ESRI consider publish their official standard basemaps in 512x512 tiling formats. That way we can use our 512x512 Raster tile layers in 3D easily.
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