Building Solids and 3D Meshes with TINs

TINs can be used to build 3D solid models as well as 3D meshes. This can be done by selecting the following commands in the Build TIN menu:

Horizons -> Solids

Horizons -> 3D Mesh

Extrude TIN -> Solid

The preferred method for creating solids is the Horizons method.

The Extrude TIN -> Solid command creates a new solid from each of the selected TINs by extruding each of the TINs up or down to an elevation specified by the user. Extruded TINs are useful in the construction of solid models of soil stratigraphy.

Fill Between TINs -> Solid

The preferred method for creating solids is the Horizons method.

The Fill Between TINs -> Solid command provides a quick way to create a solid bounded above and below by two or more selected TINs. The TIN defining the top of the boundary of the solid should be selected first. The remaining TIN(s) are then selected. All selected TINs are extruded down to an arbitrary elevation below that of all the selected TINs. GMS then performs a difference set operation.

Fill Between TINs -> 3D Mesh

A portion of a 3D finite element mesh can be constructed from two selected TINs using the Fill Between TINs -> 3D Mesh command. Typically, the two TINs represent the top and bottom of a stratigraphic unit that is to be modeled with the 3D mesh. The two TINs should not intersect in order to use this command.

Before using the Fill Between TINs -> 3D Mesh command it is first necessary to construct a 2D finite element mesh. When the command is selected, the user is prompted to input the number of mesh layers to be created between the TINs and to select the material type that will be associated with the new elements. A series of layers of 3D finite elements is then constructed between the two TINs by projecting each of the 2D elements in the 2D mesh. For example, if N layers are specified, N 3D wedge elements are created from each of the triangular elements in the 2D mesh, and N 3D hexahedral elements are created from each of the quadrilateral elements in the 2D mesh. The z coordinates of the nodes created for the 3D elements are distributed uniformly between the top and the bottom TINs.