Data identifier: HORI for a 2D horizontal model

Data identifier: VERT for a 2D vertical model

Data identifier: 3D-M for a coupled 2D/3D model i.e.. complete 3D model

Data identifier: V-3D for a 3D vertical model

7th row of the model file

When editing with the SPRING user interface, the model type is defined at the start of model creation in the dialogue File New. Since you initially always start with a 2D model, you can only choose between a 2D horizontal or a 2D vertical model type at this point in model creation.