Issue with globe and ellipsoid occlusion

CesiumJS
1

So I’m trying to draw some fairly large ellipsoids, and the behavior where the ellipsoid intersects the earth doesn’t seem to be correct. Sandcastle example: Cesium Sandcastle

I’ve got a large (approximately Earth-sized) ellipsoid, that intersects the earth, but doesn’t seem to get occluded properly. If I position the camera directly above the ellipsoid and zoom out, the ellipsoid doesn’t get occluded at all:

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If I zoom in a bit, a small portion of the ellipsoid gets occluded:

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zooming in further, the occluded area gets larger and larger.

There are other similar issues if looking from the side of the ellipsoid instead of the top. The most obviously problematic is this view - note the grey circle near Antarctica, entirely separate from the rest of the rendered ellipsoid; that’s just not geometrically possible.
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Is this a known issue? Is there something obvious I’m missing? Thanks!

2

That behavior does look strange to me.

I don’t believe the earth is occluding anything, but rather a far frustum is culling the backface.

Would you mind explaining more about your overall use case? There may be a better approach or a workaround.

3

Thanks for the response! The use case is visualizing large volumes around orbiting objects, so an ellipsoid feels like the natural approach, but certainly if there’s an alternative I’m happy to give something else a try.

I’m not sure it’s backface culling - if I construct the viewer with {globe: false} the whole ellipsoid shows up just fine, which I wouldn’t expect if that were the problem; the same is true if I make the globe semi-transparent.