About 3D tiles transform matrix

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!

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?

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!

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!