3D TILES NEXT and the ION on-premise pipeline

Cesium ion
1

With the addition of the experimental 3D Tiles Next implementation in CesiumJS 1.87.1, a number of new extensions are now supported.

Does the on-premise Cesium ION pipelines have the ability to to populate any of these new extensions? Such as the 3DTILES_Metadata and 3DTILES_implicit_tiling extensions? For example, when tiling a BIM model, can the tiler now grab the metadata from the geometry instances and add this metadata to specific tiles using the 3DTILES_metadata extension?

I’ve also noticed that c++ libraries were included with the 4.4.5 on-premise release, can this be used to add properties to tiles? It doesn’t look like the libraries were included with the latest release, not certain why this is.

Thanks for your time,
Tom

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Hello Tom,

Thanks for your questions. There has been no change to the tilers regarding metadata yet: those capabilities will be rolling out next year. However, the current plans may not cover the feature request you described (to add metadata support to the BIM/CAD model tiler). Can you please tell us more about your use case, so that we understand it as we look ahead? What is the end goal you are seeking to achieve by capturing that metadata? If you have any example source data that we could look at and possibly use for testing internally, please let us know.

To your second question, when you say that C++ libraries were included in the 4.4.5 on-prem release, do you mean this entry in the change log?

Updated documentation to include installation instructions for Microsoft Visual C++ Redistributable Packages for Visual Studio 2013

That change was made in order to fix a problem with the 3D Buildings Tiler’s handling of textures on Windows. It isn’t related to 3D Tiles Next or metadata.

Let me know if that’s what you were thinking of, or if you noticed a change elsewhere.

Thank you,
Matt

3

Thanks Matt,

Regarding the C++ libraries, my fault I must have misinterpreted the docs whilst skim reading. I assumed there was now a public API to customise the tiling process.

Regarding metadata - this has been brought up a few times in the community, I’m just bringing it up again due to the implementation of 3D Tiles Next. There are a couple of use cases which we would like to implement, ideally using ION, but it may now be possible to do this retrospectively if ION does not support this:

  • Metadata stored in BIM objects, such as the properties of a steel beam (width, height, type etc…) produced from Revit for example. To my understanding these properties can be present when exported to FBX with a bit of fiddling. Will it be possible for the tiler to include these properties under the 3D_Tiles_Metadata property?

  • With ContextCapture, and I’m assuming other reality mesh tools, we can classify parts of a mesh to hold certain properties. Would it be possible to populate the 3D_Tiles_Metadata property with these classifications?

I’m assuming this may not be possible from your response, so when I say retrospectively I’m asking if it would be possible to populate the ion generated tileset.json file with relevant properties from the raw input models. So the process may look something like the below:

  • Tile a BIM model (FBX) using ION
  • Parse the FBX model and store the geolocation and properties associated with each geometry instance
  • Parse the tileset.json file and populate the relevant tiles metadata property with the above properties, although I wouldn’t know how we could distingush which tile relates to which geometry instance. It may be easier to convert the model to gltf with properties instead of fbx

Are you aware how the metadata was populated in this sandcastle model?

Thanks for your time,
Tom

4

Hi Tom,

Thanks for writing up those details. We have opened up two feature requests specific to the cases you described: one for BIM data and one for reality meshes.

As for that Sandcastle model, that was a joint effort on the part of Aerometrex and Cesium. Aerometrex did the AI classification, and then Cesium did some internal post-processing to get it into the 3D Tiles Next feature ID texture format. That process may end up being similar to how it is ultimately implemented in the tilers we ship, but it’s too early to say at the moment. So, while the process you describe might be possible, it would require custom development work.

As a meta point, the team is glad to see that you are looking closely at 3D Tiles Next. I know you’ve already read the blog post, but I’d still like to link you to this part, which encourages users to share their thoughts on the draft spec as well as insights from their work. What you’ve described above with respect to the tilers has already been helpful, but if you’d like to comment on the spec itself, you are more than welcome.

Let us know if you have any additional thoughts or questions.

Thank you,
Matt