The color tone of “Japan 3D Buildings” has, at some point, started to look yellowish and dull. I recall it used to have a clearer appearance—could this be by design?
The color effect looks like this might, under the hood, be the same as what is reported in Brown metallic reflection and tracked in New 1.123 Environment Map Rotates Together With Model · Issue #12310 · CesiumGS/cesium · GitHub
We have discovered that the color rendering of Japan 3D Buildings varies depending on the CesiumJS version. As reported previously, Cesium 1.133 produces significantly muted colors.
In the attached Cesium 1.119 version, the colors appear clear and accurate.
Please implement a fix to ensure accurate color rendering in the latest 1.133 version as well.@Marco13
I don’t know the latest state of the investigations here, but left a comment at https://github.com/CesiumGS/cesium/issues/12310#issuecomment-3302583880
@NSZ I posted another comment in the GitHub issue. This comment includes a workaround for the underlying bug - namely, to disable the environment map manager.
A comparison of the appearances, using a Japan buildings tileset, is shown here:
Here is a Sandcastle that shows how to disable the environment map manager:
The GitHub issue comment contains further information and possible workarounds. But maybe disabling the environment map manager helps to avoid the issue for your use-case, until the underlying bug is fixed.