Three Dimensional Loading: Point loading can be specified with any combination of forces and moments and at various points in space: Vertical Loads, Fx, Horizontal Load, Fy, Horizontal Load, Fz, Rotational Bending Moment, Mxx, Bending Moment in Myy, and/or Bending Moment in Mzz, and Sets of distributed lateral loading may be specified and may be applied anywhere along the length of each pile in the group. Distributed loading may be constant or may vary linearly with depth. Distributed lateral loading may be specified in any lateral direction with the use of its components in the Y and Z coordinates and GROUP v8 allows input in local or global coordinates as well as load factors for any or both directions. Specification of Driven or Drilled Shafts. This feature introduced in intructs the program to use shapes of the nonlinear t-z curves, for transfers in side resistance, that are appropriate to the designated method of pile installation. Automatic generation of soil-resistance (p-y) curves: Soil-resistance (p-y) curves can be internally generated by the program for the following soils: submerged soft clay, stiff clay with free water, stiff clay without free water, sand (Reese et al), sand (API), silt (c-phi soils, cemented sands), strong rock (vuggy limestone), weak rock, stiff clay using k value, and liquefied sand. Internally-generated p-y curves may be printed at any depth for reviews or reference. The p-y curves selected for printing may correspond to any one pile in the pile group. In GROUP v8 the user may also specify the displacement "y" points on which to plot specific "p" values for each curve. Users may optionally input their own soil-resistance (p-y) curves for certain soil depths. A subroutine has been introduced to deal with layered soils (for example, where there may be layers of sand and clay). p-y multipliers may be provided to increase or to reduce the soil resistance (p-y) curves for any pile in the group. This feature may be used in seismic conditions to reduce the response of liquefied layers or in closely-spaced piles, to account for "Group" action. In addition, the program can automatically generate reduction factors to account for 'group' effects based on the inputted loading, piles and geometry. In Group v8.0 users can specify p-y multipliers for both orthogonal directions. Structural features: Linear interpolation of bending stiffness has been programmed for piles with varying cross sections. Nonlinear Material Properties: Users may optionally ask the program to take into account nonlinear values of flexural stiffness (EI) for any or all piles in the group. These values are specified by the user inputting nonlinear curves of moment-vs-curvature for each or all piles in the group. In GROUP v8 a feature was added to graph the inputted curves in real time so the user can visually check for errors. Another new feature is the ability to open an external text file with space-separated values of moment-vs-curvature (perhaps as exported from programs like LPILE v6). Three types of boundary conditions are available for pile-head connections to the rigid cap: pinned, fixed, or elastically restrained.In GROUP v8 different types of pile-head connections at pile caps may be specified for both orthogonal axes. Pile-Cap Stiffness Matrix: GROUP v8 can provide the stiffness and/or flexibility matrices for foundations in 2D and 3D models. These are often used by structural engineers for foundation simulation in their numerical models. In GROUP v8 users can obtain pile-cap stiffness for any load conditions. Users may also define specific points on the secant-stiffness matrix. Program can provide main diagonal as well as off-diagonal terms. Other features: Batter piles and vertical piles can be included in the same group analysis. Users are provided with the option to specify a reduction factor on the axial capacity on each pile of a closely-spaced group of piles. An optional feature can instruct the GROUP program to take into account the lateral soil resistance against embedded pile caps. Enhanced data entry: Standard Windows operations, such as dialog boxes, grid cells, clickable buttons, drop-down list of options, and pull-down menu choices are all incorporated in the program. Most cells allow the use of mathematical equations to ease certain data entries (or for occasional unit changes). Some window screens incorporate options for automatic calculation of properties based on user-specified values. The graphical interface has been enhanced in Group v8 and allows users to observe complicated geometry in three-dimensional arrangement. Users can check pile details for any selected pile within the displayed 3-D geometry. For observation of results, the improved graphical interface allows users to observe colored contours or pile diagrams of selected output parameters (contour plot or pile diagram) in the pile geometry.