Issues with Polyline & Terrain

CesiumJS
1

1. A concise explanation of the problem you're experiencing.
I have a sloped polyline that correctly draws and displays with depthTestAgainstTerrain = false. When depthTestAgainstTerrain is enabled, rotating the camera to different angles causes portions or sometimes all of the polyline to disappear, even though it should not be obstructed by the terrain as it is several hundred feet above it.

2. A minimal code example. If you've found a bug, this helps us reproduce and repair it.
[Sandcastle Example](https://cesiumjs.org/Cesium/Apps/Sandcastle/index.html#c=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)

3. Context. Why do you need to do this? We might know a better way to accomplish your goal.
I need to display a rectangular glide slope that starts several hundred feet in the air and ends at the terrain. I also need to enable depthTestAgainstTerrain as I have models that need to be displayed.

4. The Cesium version you're using, your operating system and browser.
Chrome 68 on Windows 10

I'm aware of [Issue 2172](https://github.com/AnalyticalGraphicsInc/cesium/issues/2172), but can't tell whether that will resolve this or not as most of this polyline is not tied to the terrain at all. Any help is greatly appreciated.

Thanks

2

Hello,

Thanks for the code example!

I think this is related to the logarithmic depth buffer that we introduced a few releases back.
We’re tracking log-depth and geometry issues here, but in the meantime it looks like setting viewer.scene.logarithmicDepthBuffer = false helps.
Let me know if you find any views that are still broken though.

Thanks!
Gary

3

Thank you, that definitely works better! I see a few labels sometimes getting partially obscured when rotating, but that I can live with for now. I’ll keep an eye on that issue.

Thanks for the quick response.
-Sherwin