3D surface: 

the 3D surface viewer is using the 3DHOP viewer. 

3DHOP (3D Heritage Online Presenter) is an open-source framework for the creation of interactive Web presentations of high-resolution 3D models, oriented to the Cultural Heritage field (https://3dhop.net/).

The use of 3DHOP allows to display very high resolutions models at high speed using tilled 3D models. The user can also modify the light source, take measures and define sections.