Positioning 3d-tiles in columbus view

1. A concise explanation of the problem you’re experiencing.

How to position 3d tiles correctly to map tiles? I am using the New York model from sandcastle to show that with Columbus view buildings go to wrong position.

Is there a minimal example where 3d tiles model is positioned correctly on a webmercator projection Columbus view?

2. A minimal code example. If you’ve found a bug, this helps us reproduce and repair it.

3. Context. Why do you need to do this? We might know a better way to accomplish your goal.

4. The Cesium version you’re using, your operating system and browser.

Newest version, Chrome

Thanks for reporting this. I think I know why this is happening, but I’m not sure what an easy fix for this would be. I posted some thoughts and details on this in a GitHub issue:

https://github.com/AnalyticalGraphicsInc/cesium/issues/7915

Hopefully we can get some thoughts when others on the team have a chance to give it a look as well.

We had time to investigate this more and one important condition applies to our use case => Our 3d tilesets use flat projections. So in a way, fixing the new york tileset is not relevant - and it is not even feasible as that tileset is already projected to curved globe.

But good news is that this branch tackles the issue very well:

https://github.com/AnalyticalGraphicsInc/cesium/tree/projections

I wish your team could merge this to master! It is a very promising solution.

An idea: the projections branch has quite many complex changes to the code base. I have been wondering if map projection functionality could be added to SCENE3D mode without so many changes => just make the globe ellipsoid a flat surface and thats all?

Thanks for digging into this and posting your update. That’s good to hear that you’ve found the projections branch useful! It does attempt to allow for arbitrary 2D projections so I think that’s part of what makes it so complex.

Are you able to share a sample of your 3D Tiles with flat projection and how you’re using the projections branch to get it to render correctly? If you have a simpler solution to propose in a pull request, I think that will be more likely to get merged in master sooner.