Buildings not showing

[yacine...@gmail.com]

Hello,
I converted the coordinates of some buildings in ECEF and I want to show them in Cesium.
The json file is well loaded and it’s well positioned (its bounding box with the inspector) and the triggering of the loading of the file b3dm is done. now either the coordinates of the b3dm file are bad, or for one reason or another the model is not displayed.

[Kacem Yacine]

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[yacine...@gmail.com]

B3DM coordinates are in ECEF (should be adjusted later - ie tile centered with either use of CESIUM_RTC extension or via 3D-TILE Matrix). So the model should flick but for testing it's not a problem.
What should we test now ? What parts of the cesium code should we debug to find why the model is not displayed ?
What we already tracked is that the code involved in the loading of the D3DM file is called, but how to find why it is not displayed ?

[Gabby Getz]

To debug, I would take a look at Batched3DModel3DTileContent.js. That's what handles the content of the b3dm tiles, which is where the error seems to be since the bounding volume is correctly positioned. My guess is that you should be defining the positions relative to your root tile, and not in global ECEF coordinates.

Thanks,

Gabby

[Sean Lilley]

If you are able to post building_1.b3dm that would help too.

[Kacem Yacine]

Thanks for your replie,

I Attached the GLB files before and after the coordinates’ conversion from geographic to ECEF and the B3DM file (ECEF Coordinate)

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[yacine...@gmail.com]

Thanks for your reply,

In another pipeline (for non textured buildings), we generate GLTF directly and make use of the CESIUM_RTC extension to avoid problems caused by large ECEF coordinates.
In this new pipeline for textured buildings we convert 3D Collada files to B3DM using collada2gltf - we know that direct use of ECEF coordinates in B3DM will cause jittering effect and we plan to solve it using a transform matrix in the master Json file. But at this point, it should work - with jittering - with ECEF coordinates or are we missing something ?

[Sean Lilley]

Thanks for sending the files over.

Your tileset is almost correct, but almost all of the nodes in the glTF have a matrix that is translating the model away from its ECEF position.

      "matrix": [

        1,

        0,

        0,

        0,

        0,

        1,

        0,

        0,

        0,

        0,

        1,

        0,

        551778,

        2800217,

        0,

        1

      ],

After replacing 551778 and 2800217 with 0 the model is placed correctly (screenshots attached).

[yacine...@gmail.com]

Thanks Sean for pointing out this problem. Input data were wrong.