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
Figure
GLOBAL
Defines the global coordinate system as the current LCS.
CURRENT LCS
Creates a local coordinate system as the current LCS.
LAST
Defines the last coordinate system as the current LCS.
VIEW DIRECTION
Defines the view directions as the W-Axis
of the current LCS.
The user can select or define a point as the origin, or the origin of the
global coordinate system can be the origin of the current LCS.
There are two ways to create a LCS based on whether the DEFINED BY 3 LOCATIONS toggle is checked.
1. CHECKED (ON)
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.
l ONE 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.
l TWO POINTS
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.
l THREE POINTS
Select three points P1, P2, and P3. The point, 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. The V-axis is determined by the cross product of W x U.
2. UNCHECKED (OFF)
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.
l Select DEFINE ORIGIN, and the INPUT COORDINATE dialog will appear. Select a point or node as the origin, and then select OK.
l Select one of the AXIS buttons to define the axis in the LCS dialog.
l Select BY POINT or ALONG AXIS from the U/V/W
AXIS dialog (Figure
l Select OK from the AXIS dialog.
l Select OK from the LCS dialog.
Note: If the local coordinate system is not acceptable, use the NO button to reject and redefine the coordinate system.
l The coordinate system is displayed.
Figure