Hello everyone! I am a beginner and I would like to know how to use cesium ion to convert a model into tiles output from multiple LODs. If this LOD is controllable, that would be even better! Thank you!
Hi @jingyangking ,
Welcome to the Cesium community.
What type of data is contained in the model? Cesium Ion offers several tilers for different types of data. The instructions on how to upload will be slightly different for each one. There are links on the data formats page for each one.
Converting a model into 3D Tiles using Cesium ion will automatically add different LODs. These are optimized for streaming the data and are not something that is currently controllable. If you find that the LODs produced by our tilers are not meeting your needs, please let us know more information about your use case.
Regards,
Thank you for your reply. My model is BIM, with a format of. RVT. I have converted it into three types: FBX/GLB/OBJ. Currently, I have used FBX for tile conversion and I can see that many b3DMs have been generated. However, I am not sure which b3DMs are LOD0 and which are LOD1. These LODs are not well classified and are all unified in one folder. I analyzed the information of the converted b3DM and found that the attribute information in the original BIM was lost. I’m not sure if this is due to attribute loss during format conversion. Or is it that FBX caused attribute loss during the process of generating tiles. I hope you can give me an answer, thank you!
The tileset.json file would have the structure of the 3d tileset including which of the B3DM files were used at each level of detail. Can you provide more details about why you are trying to individually access the different LODs? Typically this is something that viewer (such as CesiumJS) manages and you as the developer just need to point it to the tileset.json.
The GLTF format does have some support for metadata, however I am unsure if our tilers currently support it. I have reached out to some of my collages who are more familiar with this to see if they can provide more detail. We do have being able to support BIM metadata on our roadmap.
Thank you for your reply! Classifying LODs at different levels will make the overall file structure more aesthetically pleasing,like this:
, but I can also manually implement this, although it may be a bit cumbersome. For the loss of attribute information, I found that it is related to 3dtiles. b3dm contains batchtable and featuretable, which include the attribute information contained in the object. However, by parsing these converted b3dms, I found that the content of the featuretable is 0 in length and there is no corresponding batchtable, which leads to the lack of attribute information in the entire tiles. If you want to display the corresponding attribute information, you need to add the content in the batchtable. However, this requires some tedious process, and it is difficult for me to complete this task.
Thank you for that additional information.
I have confirmed that our existing model tiler does not have support full bringing metadata through from the source data. This is an area that we are working on improving.