COORDINATE SYSTEM
The functions in this menu are used to create and modify local coordinate systems. The functions are shown in Figure 9.13.1.
Clicking the horizontal scroll bar changes the size of the displayed coordinate system. Select APPLY when finished.
COORD. SYS. ON
Toggles all created coordinate systems ON/OFF.
A detailed description of these functions is given in the following sections.
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.
DELETE COORDINATE SYSTEM
This function enables the user to delete a local coordinate system from the database.
The SELECT LCS dialog window appears, see Figure 9.13.4.
-- Pick a
coordinate system.
-- Drag
a window to include the coordinate system.
--Define a
multi-point region to include the coordinate system.
C.S. ID
Enter the starting and ending coordinate system ID and the increment in the next dialog window.
REJECT
Reject last selection.
Note: To remove the local systems/definitions from individual nodes, the user must reassign the nodes to the global coordinate system.
COPY COORDINATE SYSTEM
This function copies a selected coordinate system to a new location.
The SELECT LCS dialog window appears with only two options activated.
1. Pick the desired coordinate system displayed on screen using the default mouse pick or select GLOBAL C.S. to select the global coordinate system.
2. Define the new location using the INPUT COORDINATE dialog window. The selected coordinate system will be copied automatically.
MODIFY COORDINATE SYSTEM
This function is used to modify the definition of an existing coordinate system.
After a coordinate system is selected in the SELECT LCS dialog window, the SELECT OPTION window is displayed. See Figure 9.13.5.
If MOVE is selected, the INPUT COORDINATE dialog window appears. The selected coordinate system will be moved automatically after a new location is defined.
If ROTATE is selected, the user must enter a rotation angle in the next dialog window. The coordinate system will be rotated automatically.
CURRENT COORDINATE SYSTEM
This function allows the user to designate a CURRENT status to a selected coordinate system.
The user selects a coordinate system by cursor.
The selected coordinate system will be highlighted and the last one changes its color.
IDENTIFY COORDINATE SYSTEM
This function is used to identify the type and origin of a coordinate system.
Select a coordinate system by cursor.
After a coordinate system is selected, eta/DYNAFORM prompts:
C.S. #### [SYSTEM TYPE] ORIGIN (x y z)
Where:
#### is the coordinate system numbers.
SYSTEM TYPE is the system type (rect.,
sphere, cylin.) and ORIGIN is the global
location of the system origin.