LOCAL COORDINATE SYSTEM

eta/DYNAFORM refers to the local coordinate system to translate, rotate, mirror, copy, and generate points, lines, or nodes. When such a function is selected, the program will automatically prompt the user to generate a local system designated as the UVW coordinate frame. The LCS dialog window will be displayed (Figure 2.5.1). The user can create a new LCS or select a system as the current LCS by selecting GLOBAL, CURRENT LCS, LAST, VIEW DIRECTION.

                                                   

  

    

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 GLOBAL

Defines the global coordinate system as the current local coordinate system

      CURRENT LCS

Uses the current local coordinate system.

       LAST

Uses the last defined coordinate system as the current local coordinate system.

There are two ways to create a LCS. The two different methods are dependent on whether the DEFINED BY 3 LOCATIONS toggle is checked.

        1. CHECKED

The user can select one, two, or three points/nodes to create a system. To select a  node, choose NEAR NODE. To select points, choose NEAR POINT.

Select a point and choose OK. The created LCS has an origin at the selected point and is a translation to the origin of the global system

Select two points and choose OK. The first point is the origin. The W-axis is the vector from the first point to the second point. The LCS is a translation and a rotation from X to U of the global system.

Select three points P1, P2, and P3. The P1 is the origin. The vector P1-P2 is the U-axis. The cross product of U and the vector P2-P3 is the W-axis and the V-axis is determined by the cross product WXU.

          2. UNCHECKED

DEFINE ORIGIN, U-AXIS, V-AXIS, and W-AXIS will be activated. To create a system in this case, the user needs to define an origin and axis. The LCS system will be a translation and a rotation of the global system.

Note: If the local coordinate system is not acceptable, use the BACK button to reject and redefine the coordinate system.