In this example use the central slider to see the before construction and mid way through construction effects.

 

 

This effect can be used to show elevation data also – see this example of an area of National Trust land in Surrey – Red being the higher ground and Blue the lower:

 

 

Another example, this time at The Royal Automobile Club, Woodcote Park near Epsom, where Surrey Visuals are providing progress reports on the construction of a families centre within a walled garden:

 

 

In this example you can clearly see where some tree felling has taken place: