Overview Of Coordinate System Workplane Concept
- World Coordinate System
- Coordinate System
- User Coordinate System
- Element Coordinate System.
Element coordinate system is only used for element specific jobs, like assigning loads, viewing analysis results, etc. Other three can be used for creation and editing commands.
Only one coordinate system of the three can be active at a time. The active coordinate system is called the Active Workplane. It is the XY plane of the active coordinate system. Active workplane (or active coordinate system) can be switched between world, view and user coordinate systems at any time. When a new project is created, active workplane is set to world coordinate system.
If users wish to set up workplane with different view, please refer to Setting Up the Workplane. Workplane is displayed as a pair of axes, which are the X and Y axes of the currently active coordinate system (active workplane):
Red arrow indicates the X-axis and green arrow indicates the Y-axis.
In general all element creation commands and editing (copy, move, rotate, etc.) commands work in active workplane.
World Coordinate System (WCS)
Global coordinate system is named as World Coordinate System. There is only one World Coordinate System and it can not be changed.
View Coordinate System (VCS)
Every View window has its own local coordinate system. Coordinate system of views created with Create Global 3D View are the same as World Coordinate System.
User Coordinate System (UCS)
In addition to WCS and VCS, users can define a coordinate system which is independent of views or WCS. This is called User Coordinate System. User can not create multiple User Defined Coordinate systems at a moment. In other words, when the user creates another user defined coordinate system, the previous user defined coordinate system is replaced with the new one.
Element Coordinate System
Each element (member) has its own element coordinate system. Element coordinate system is a right handed Cartesian coordinate system which has a default orientation. It is used to define frame element end releases or to view the element force output. Element coordinate system axes are denoted by 1, 2 and 3.
Frame Element Local Coordinate System
Local 1-axis is directed along the line connecting start and end nodes. The positive direction of the axis 1 is directed from start node to end node. The other two axes lie in the plane perpendicular to the axis 1 and they are oriented according to a specified angle, which is called rotation angle. Rotation angle is specified with respect to the default orientation of the frame element.
Default orientation of local coordinate system: