Is sampleTerrainMostDetailed a http request?

In my application I am using sampleTerrainMostDetailed in some situation in order to get an altitude above the ground.

I was wondering if this is an http request to the cesium server in order to retrieve the altitude on a dataset, or if it is a cached value based on the tile already downloaded.

Thank you

I think it will use the cached data if it’s already been requested. You can see the source here: