Upload 3D tiles on cesium ion Textures No Display

“why after I upload 3d tiles (files included .json and .b3dm) in the assets cesium ion, the tileset is not showing the model and textures, but only show the outline of the structure”

Note that, I have converted the file from sketchup to .obj using FME (output with textures, .mtl and .obj).
And then I converted that whole file of obj to ‘cesium 3dtiles’ using FME (output with .json and .b3dm)

Attached image is the example of preview 3d tiles after upload to asset cesium ion.

Welcome to the Cesium Community!

The 3D Tiles output from FME may be missing some attributes required to properly display on Cesium ion. Have you tried directly uploading the obj file to Cesium ion and tiling it there instead?