You’ll want to convert it to ECEF. The b3dm’s themselves are expected to be ECEF, no coordinate information. However you may define WGS84 lat/long rectangles for the bounding volumes in the tileset.json file.
Are you saying that If I set the bounding volumes, I can make 3DTiles with that file?
Additional questions.
can i set coordinate(WGS84) to tileset.json file? I thought I was only a ECEF.
The b3dm file will need to be updated to ECEF. The tileset.json however can use WGS84 lat/long coordinates if you decide to use the “region” bounding volume type. Otherwise the “sphere” and “box” types are ECEF.