Entities in a DataSource with clustering enabled disappear when the camera zooms in below ellipsoid

[zachsussman]

Sandcastle example: https://sandcastle.cesium.com/index.html#c=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

Initially, the red point is visible. Zoom in a bit and it will disappear; zoom back out and it reappears.

Browser: Google Chrome, Version 115.0.5790.170 (Official Build) (64-bit)

Operating System: Ubuntu 20.04

Before:

After zooming in:

[ggetz]

Thanks for the report @zachsussman! I can reproduce this.

I don't think this necessarily has to do with clustering. I see similar behavior when I comment out the line
dataSource.clustering.enabled = true;

Notably this only occurs when the entity is a a negative height. I beleive this is due to the depth plane. Some additional details and possible workarounds are detailed in #7879.

I'm also going to close this as a duplicate of #7879, but will add your report there.

[zachsussman]

Thanks @ggetz! Unfortunately, it looks like clustering is related after adding depthPlaneEllipsoidOffset. With clustering on, the issue still happens, while with clustering off, depthPlaneEllipsoidOffset fixes the issue.

I'll post this to the linked issue.

[ggetz]

Since this is specific to clustering, I'll reopen the issue. Thanks!