In order to depict details such as local geological faults, clay lenses, localised groundwater aquifers, etc. in a 3D model, vertical mesh refinement is often necessary (thinner layers).

If an element layer is to pinch-out, the Z coordinates of the lower node layer and the upper layer must be identical for all corresponding nodes.

The parameter ZEPS, which is stored in the 3d file, determines the accuracy with which the Z coordinates are considered identical and are therefore merged. The default setting is a value of 0.01 m (i.e. if the Z coordinates of two adjacent nodes are less than or equal to 1 cm apart, the nodes are merged into one node). The value can be changed by the user in the Mesh 3D Threshold for collapsing layers... menu item

Threshold value for coinciding layers

The model check recognises merged/dropped nodes and elements so that the calculation programs only process the remaining data.

Realization in SPRING