Tiling-pipeline causing faceted / crinkly 3d tileset output

We’ve been having issues with the Cesium ION Engine model-tiler for some time now, specifically for BIM/CAD models. The majority of issues have been resolved by moving the model closer to the origin, but we are still seeing issues for models which span a distance of over 200m+. This is a big issue for us as we have a large number of rail projects which are required to be visualized in CesiumJS.

The resulting Cesium3DTiles end up looking like the below (other models are much worse than this):

This model spans approximately 1700m. The model has been moved to a local origin, centered around 0,0,0. This ‘faceting’ issue is consistent across the whole 1700m span of the model.

This model initially doesn’t have any issues when in fbx format. I have also converted them to gltf using the fbx2gltf cli, applying/not applying –blend-shape-normals & --blend-shape-tangents arguments to test the output. The fbx file looks fine in Autodesk Navisworks, and the gltf files also look fine in CesiumJS:

This has been a consistent issue for us, are there any tips you can provide for solving this issue? Splitting the models up into smaller sub-models isn’t an option, as this is far too time consuming. We also can’t load the gltf/glb directly instead of Cesium3DTiles as the file sizes are rather large, and our application is based around loading cesium3dtiles.

Currently using 3d Tiling Pipeline 4.4.2, we have also uploaded the models to Cesium ION.

glb asset id: 400972
fbx asset id: 401092

Any help you can provide is appreciated.