Bug: seam if using depthTestAgainsTerrain:false

v12424124_34 · August 4, 2021, 8:18pm

There is a big seam where-ever tileset should be underground when using depthTestAgainstTerrain:false.

Any ideas what to try with this?

edit: It is maybe a duplicate of this:

github.com/CesiumGS/cesium

Depth plane causing clipping artifact

opened 10:29PM - 29 May 19 UTC

OmarShehata

category - graphics type - bug

I've run into this with various 3D Tilesets, but this is a good minimal example …produced by Adam Twite in [this forum thread](https://groups.google.com/d/msg/cesium-dev/25wlWeLRPII/6x112pjpAwAJ): [Sandcastle](https://cesiumjs.org/Cesium/Build/Apps/Sandcastle/#c=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). Just try tilting the camera up a bit. ![depth_plane_czm_man](https://user-images.githubusercontent.com/1711126/58595504-e13d8780-823e-11e9-9c7c-00f2f7f5adf0.gif) Here, the 3D model is actually underneath terrain, but depth testing is turned off, so it should show through. It clips because the depth plane (which is used to write depth on the ellipsoid when the globe tiles don't, so that things on the opposite side of the globe don't show through). You can verify this by commenting out the `depthPlane.execute` line here in Scene.js: https://github.com/AnalyticalGraphicsInc/cesium/blob/master/Source/Scene/Scene.js#L2307

v12424124_34 · August 5, 2021, 4:37am

For me that mentioned PR Fix for clipping and camera navigation issues below ellipsoid by chris-cooper · Pull Request #9200 · CesiumGS/cesium · GitHub does not work but setting

My eventual solution:
scene.logarithmicDepthBuffer = true seems to be best to combat this issue

sam.rothstein · August 6, 2021, 12:29am

@v12424124_34

Thank you for your detailed forum post! I looked over your solution and it seems robust I will share this thread with other community members if similar issues arise in the future.

-Sam