CREATE COORDINATE SYSTEM
This function is used to create a coordinate system.
Enter coordinate system ID and select OK in the next dialog window. The LCS dialog window appears, see Figure 9.13.2
As mentioned in previous chapters, this window is displayed when a current local coordinate system is needed. In those cases, the user can create a new LCS or select a system as the current LCS by selecting GLOBAL, LCS, or LAST.
GLOBAL
Defines the global coordinate system as the current local C. S.
LCS
Creates a local coordinate system as the current local C. S.
LAST
Defines the last coordinate system as the current local C. S.
There are two ways to create a LCS based 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.
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.
TWO POINTS
Select two points and choose OK. The first point is the origin. The U-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.
THREE POINTS
Select three points. 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 active. To create a system in this case, the user needs to define the origin and an axis. The LCS system will be a translation and a rotation of the global system.
Select DEFINE ORIGIN. The INPUT COORDINATE dialog appears. Select a point or node as the origin and select OK.
Select one of the AXIS buttons to define the axis in the LCS dialog.
Select BY POINT or ALONG AXIS from the U/V/W AXIS dialog (Figure 10.13.3) to define the axis. If BY POINT is selected, select a point in the display window to define the vector for the desired axis. If ALONG AXIS is selected, a dialog is displayed. The choices are ALONG X, ALONG Y, ALONG Z, ALONG U, ALONG V, ALONG W in the next dialog window select one and then DONE.
Select OK from the AXIS dialog.
Select OK from the LCS dialog.
The coordinate system is displayed.