Converting DAE tileset to 3d Tiles

CesiumJS
1

Hi all,

Please excuse my noobness.

I have a tileset of DAE files as a LODTreeExport. The metadata is contained in XML files.

Can someone please point me in the right direction for converting this tileset?

I realise I have to convert the individual dae files. But is there a way to convert the metadata? Or will I have to recreate it all by hand?

Thank you so much for your time

Cheers,

Alex

2

As of now there isn’t an automatic way to do this conversion, but here are some steps that will help:

First you will need to convert the DAE files to gltf, and then to b3dm tiles. Check out COLLADA2GLTF. Batching models together into a tile is a pretty involved step and will require combing multiple gltf’s into a single gltf, where models are differentiated by a BATCH_ID vertex attribute. Some of this is described in the b3dm spec but you will need to write all the code yourself.

The metadata that defines the tree hierarchy will need to be converted to a tileset.json file, which is also a tree structure. If you have per-feature metadata, that will need to be incorporated into a Batch Table inside each tile.

Out of curiosity are you using Context Capture to generate the LODTreeExport?

3

Hi Sean, thanks so much for your response.

I am indeed using Context Capture.

I also have a KLM export. Is that any easier to convert to 3D tiles? Stitching the DAE files together seems fraught with difficulty. I don't suppose there's any tutorials or relevant blog posts (have Googled btw, but haven't found any so far).

Thanks again for your help

4

Hi Alex,

The latest version of ContextCapture support 3D Tiles export. Have you tried it? See https://www.acute3d.com/web-publishing-with-cesium/

Patrick

5

Hi Patrick,

Unfortunately we no longer use ContextCapture.

We've managed to convert some .dae files to gltf, but how to convert the entire tileset to a functional 3D Tiles set, with root.json etc, is a bit beyond us at this point. Not exactly sure where to start.

Is there a documented way to produce this metadata? Or could you please point us in the right direction?

Thank you so much for your responses.

BR,
Alex

6

The tileset.json structure should mirror the LODTreeExport pretty closely, though I’m not too familiar with the format to say for sure. Then for each tile you’ll need to generate a bounding volume and geometric error. If you know the min and max longitude/latitude/height of each tile you can create bounding regions (array of [west, south, east, north, minHeight, maxHeight]). The geometric is up to you, I’m not sure what the tree structure is like but tiles higher in the tree will have higher geometric error and leaf nodes will be 0.0. One common approach is finding the length of the diagonal of the tile.

For further ideas and direction you may want to check out the tileset.json structure in the spec if you haven’t already: https://github.com/AnalyticalGraphicsInc/3d-tiles#tile-metadata.

7

Hi all,

I have been trying to transform a model 3D in format .gltf to a tile3D, but I haven't had success. I have used 3D tile generator https://github.com/AnalyticalGraphicsInc/3d-tiles-tools/tree/master/generator, however I don't obtain the correct tiles. I don't completely understand the process because there are some values in the source which seem to be a bit random.

I don't kown if I am doing something worng. or if another software exists to create tiles 3D from .gltf or other format such us .dae

Thank you so much for your time.

Sergio

8

That project is not a general purpose tool for generating 3d-tiles from gltf models, but more so a demonstration of all the different tile formats and options available to them, and how someone might code these things themselves. There are hardcoded values in many places because it is used to generate the test tilesets in Cesium and https://github.com/AnalyticalGraphicsInc/3d-tiles-samples. We actually have an issue to rename that project so it is less confusing.

In terms of converting a glTF to a b3dm, the glbToB3dm command in https://github.com/AnalyticalGraphicsInc/3d-tiles-tools/tree/master/tools is the closest thing we have at the moment. You will still need to create your own tileset.json file.

9

Thanks so much for you response.

If I have correctly understood, I can use glbToB3dm command to create tiles 3D from a model in .gltf and a tileset.json, which difines each tile that will be create.

Sergio

10

The tileset.json needs to created by you, the tool does not generate it.

11

Hi Sergio,

We are working on 3D Tiles converters as part of cesium.com. If you can send me some sample data, pcozzi@agi.com, I’ll see if we can convert it.

Thanks,

Patrick

12

I wrote tileset.json for my data. And converted each tile from gltf to b3dm, but my data it relative and I dont know how to add the center point for each tile.

The model is loaded to cesium without errors but i dont see the model.
Please help

13

Have you tried uploading your models to https://cesium.com/ion? You should be able to get a 3D Tileset that way and you can reposition it after tiling as well.