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.

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 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.

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.