# 4.18.2. PDelta Transformation¶

geomTransf('PDelta', transfTag, '-jntOffset', *dI, *dJ)
geomTransf('PDelta', transfTag, *vecxz, '-jntOffset', *dI, *dJ)

This command is used to construct the P-Delta Coordinate Transformation (PDeltaCrdTransf) object, which performs a linear geometric transformation of beam stiffness and resisting force from the basic system to the global coordinate system, considering second-order P-Delta effects.

 transfTag (int) integer tag identifying transformation vecxz (list (float)) X, Y, and Z components of vecxz, the vector used to define the local x-z plane of the local-coordinate system. The local y-axis is defined by taking the cross product of the vecxz vector and the x-axis. These components are specified in the global-coordinate system X,Y,Z and define a vector that is in a plane parallel to the x-z plane of the local-coordinate system. These items need to be specified for the three-dimensional problem. dI (list (float)) joint offset values – offsets specified with respect to the global coordinate system for element-end node i (the number of arguments depends on the dimensions of the current model). dJ (list (float)) joint offset values – offsets specified with respect to the global coordinate system for element-end node j (the number of arguments depends on the dimensions of the current model).

Note

P LARGE Delta effects do not include P small delta effects.