# Local directions

By pressing button ​​ local directions zones can be defined. Local zone describing some polygonal area in which orthogonal local plain located X’-Y’ coordinate system is rotated on user defined angle around local Z’ axis:

Rotated local coordinate system (125,45 deg CCW) in 8-nodal polygonal local zone defined in 2D-plate package:

Rotated local coordinate system (125,45 deg CCW) in 8-nodal polygonal local zone defined in 2D-Wall package.  Note: 2D-Wall package structure is lying in global X-Z axis plain, while local coordinate system for the same structure is defined by orthogonal X’-Y’ axis.

All the results (forces, stresses, required reinforcement, deflections etc.) are represented in local X’-Y’ coordinate system independent from package type.

Rotation of local coordinate system could be performed by definition of polygonal local zone by pressing button :

Positive in degrees defined rotation angle describes contra clockwise rotation of plain located local coordinate system X’-Y’ around Z’ axis. Rotation angle itself could be manually defined by manually entry in to edit field, also by picking two points using related button. Picking two points action let define direction vector which contra clockwise rotation angle is automatically filled in to the edit field “Angle”.

#### Default situation:

Structure defined without using local anyway represents results in local X’-Y’-Z’ space which are unique over whole the structure. Default, not rotated local coordinate system, is parallel to the global coordinate system using 2D-Plate package. Using not rotated local coordinate system in the 2D-Wall package, local X’ axis is parallel to the global X axis, local Y’ axis is parallel to the global Z axis and local Z’ axis is parallel to the global Y axis.

 Default local coordinate system for 2D-Plate package Default local coordinate system for 2D-Wall package

Parts of the structure are not covered by user defined local coordinate zone(s) belongs to the zone(s) with the default local ccordinate system

All the calculated results are represented in local X’-Y’-Z’ coordinate space.

Definition of reinforcement goes in local defined X’-Y’ plane, where primary reinforcement is located parallel to the X’ axis, secondary – to the Y’ axis.  Rotation of local coordinate system by defining of local zone(s) automatically rotates applied reinforcement.

Definition of local zones doesn’t require complete recalculation of results using FEM processing in case results could be linearly decomposed (simple rotation of elastic calculated forces and stresses).

Definition of local zones automatically removes results are calculated by nonlinear processing.

Recalculation of FEM results automatically re-mesh whole structure taking in to account new presence of local zones.

Representation of some results (forces, stresses, etc.)  using predefined local zones could cause gap(s) in representation, while discontinuity of  represented function on the boundary of local zone.

Discontinuous chart of bending moments Mx on boundary of local zone before re-mesh

Discontinuous chart of bending moments Mx on boundary of local zone after re-mesh

Discontinuous chart of As,req on boundary of local zone after re-mesh