About 3D tiles transform matrix

General
1

Hi Cesium community!

Now I’m trying to run with the 3D Tiles example what it in git repo and then I got some trouble with editing the tileset.json.

I choose the ‘TilesetWithDiscreteLOD’ - the dragon statue example - and I think it’s position is explained at “transform”. So, I tried edit the last four elements in 4x4 affine matrix then I expect that four element means X, Y, Z, 1.

As you know, 3D Tile is z-up-axis and unit is meters so I edited the Z element then height position is changed. But editing X and Y element is not working as I expected(not working simply X, Y meters). This statue is near by “615 Swedesford Rd” - that is lat 40.038588 // lon -75.613250 - but I do not know what 1215107.7612304366, -4736682.902037748 means exactly.

How can I interpret the last four elements and moves the statue where I expecting?

Please give me some hint or advise. Thanks!

2

Welcome the Cesium community!

The coordinate system used here is ECEF, you can read more about it here in the spec: https://github.com/CesiumGS/3d-tiles/tree/master/specification#coordinate-reference-system-crs

What kind of project are you working on?

3

Thank you for your link and I’m checking out :slight_smile:

Our company is dedicating 2D GIS and Analytic Rendering but I got a mission what develop the 3D GIS - and check possibility of the Digital Twin.

Cesium is inspiring me and the entire world. Always thanks for your works!

4

Thanks for the kind words! If you have 3D data you want to tile into 3D Tiles, you can upload it to Cesium ion (https://cesium.com/ion/). You can see a list of currently supported formats: https://cesium.com/docs/tutorials/uploading/.

Let me know if that works for you!