Tileset bottom gets automatically stretched until it touches the terrain

Hello we have a project where we use KMZ/Collada models to represent facilities/buildings.

When uploading these kmzs into cesium ion and after the tiling process, we observe that for some of the buildings the lower part of the building gets stretched to the bottom until touching the terrain.

Here one example:

Original dae model which is contained in the KMZ:

Tiled result:

Is that something that happens as a part of the tiling process?

If yes, under which circumstances? We have some other models where this effect cannot be observed, for example this one, where the building is actually “flying” because the altitude an tilting is not correctly set.

We’d appreciate some insights that’d allow us to understand this effect and how to control or avoid it.

Thanks a lot.

Hi Miguel,

When you upload your data, do you select the Clamp to terrain option? This is part of that feature: we add a “skirt” to the bottom of each building so that it becomes flush with uneven terrain.

If you tell us more about how you would like to control this (and any other details about what result you would like to see), I’d be happy to open a feature request.


Hi Matt,

thanks a lot for the response. We select the reference terrain “Cesium World Terrain” when uploading the model", is that what you mean with clamp to terrain?