Display Offline terrain with Cesium Unreal Plugin

Hi,

i try to display 3DTiles from a local server on my machine.
(i am a very beginner in Cesium and Unreal Engine)

=> A dragon is displayed.

if i use:
file:///C:/Projets/UnrealEngine/SamplesData/Test3dTiles/tilesets/TilesetWithDiscreteLOD/tileset.json
=> Buildings are displayed

But if i use file:
file:///C:/Projets/UnrealEngine/SamplesData/Test3dTiles/tilesets/TilesetWithTreeBillboards/tileset.json
Nothing is displayed. Why ?

i have also tried to display this sample terrain of Lyon from:

Nothing is displayed. Why ?

My goal is to test if it is possible to use 3DTiles Terrain offline on a local machine (and how).

Regards,

In general, you can use 3D Tiles terrain data from a local machine. Some details are given at Adding Local Data | cesium.com , but you actually already did it correctly, by setting the Source to be a URL that points to the local file.

The reasons for the the two tilesets not being displayed are different ones:


For the TilesetWithTreeBillboards, it will print a message (in the output log that can be shown with “Window → Developer Tools → Output Log”), saying

No loader registered for tile with content type ‘’ and magic value ‘i3dm’.

This just means that the tileset uses Instanced 3D Models (I3DM), which are not yet supported by Cesium For Unreal, but will probably be supported in a future version.


For the “Temporal Lyon” data set that you linked to, it’s … a bit more complicated. The data set has some issues. For example, it declares strange transforms and bounding volumes, like

“transform”: [1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 1841958.443, 5175950.416, 194.769, 1.0]

When “fixing” these pragmatically (with a text editor), it does display something, but the result is likely not the intended one: The data set uses an extension that is called 3DTILES_temporal. I don’t know any details about this extension, but it is not supported by Cesium For Unreal (and probably not by CesiumJS either - it seems to be a proprietary one, mentioned in [3D Tiles] What is tileIndex ? · Issue #1039 · iTowns/itowns · GitHub , but not available under the given link…). On top of that, the glTF data that is contained in the B3DM has 14 validation errors (but these are only related to the accessor bounds - so the glTF is invalid, but could still be rendered by Cesium For Unreal).


So in general, if you have a (valid) terrain data set that uses the most common content type (namely, B3DM or composite tiles), you should be able to display it with Cesium For Unreal by just setting the URL as you did it. But when the data set is invalid or uses features that are not supported yet, you may encounter different issues that would have to be sorted out on a by-case basis.