If you selected one column and the spread footing option, the Isolated Spread Footing screen displays, as shown below.

First, input the configuration information. You can specify the footing size in one of two ways. First option is to select User Input and then specify length (X) and width (Z). Second option is to select the From Library and then choose one of the footings from the Description list (which you defined under the Libraries | Footing Configuration option). If the footing is symmetrically placed (concentric) under the column (which is the most common case) select concentric under column option. However, if the footing is not concentric under columns, select Eccentric under column option. In this case, input the values in the text boxes as the distance between the left edge of the footing to the center of the column.

Spread/Cap Depth is the depth of the bottom of footing. Length and width multipliers can be specified only when footing From Library option is selected. These are the factors that will be multiplied to the original footing length and width defined under the Libraries | Footing Configuration option. For example, if you have a 2 x2 square footing in Library and input 2 and 3 for the length and width multipliers, the size of the footing used in the design will be 4 x 6 m.