Define UCS

This command enables to create a local coordinate system. It is a similar dialog box to the command Geometric Registration, but here no object is moving. The command allows also editing the position and the aspect of any coordinate system.

A new coordinate system is automatically displayed in the graphic zone. By default, the new coordinate system is initialized at the place of the active coordinate system (when there was no selection). Otherwise, the position of the selected system is used.

• Change the origin of the coordinate system with the button (see Define points). The software will ask you to enter a point. Once you have input a point, you may use the fields X, Y and Z next to the button, which represent the new coordinate value of the entered point. You can also use dX, dY and dZ to apply a translation to the X,Y,Z coordinates.

• Select the axis X, Y or Z corresponding respectively to:

  • The first axis, which is horizontal and corresponds to the cyan color. The orientation you will give to this axis will always be respected. Click on the button to modify this axis

  • The second axis, which is vertical and corresponds to the orange color. The orientation you will give to this axis is respected only if (by chance) it is perpendicular with the first. Otherwise, the software will evaluate the best (nearest) axis corresponding to the direction you enter. Click on the button to modify this axis.

  • The third axis will be determined automatically to make a direct coordinate system X Y Z.

First and second axis are defined using buttons on the right of the dialog box (see Define normal direction).

When the result is correct, click OK. If the coordinate system is active, all further transformations and computations will be made in this coordinate system.

To enable/disable this coordinate system, use the contextual menu or use the "switch" button on the right of the object in the tree. Only one coordinate system can be active at any time. When a User coordinate system is deactivated, the World coordinate system is automatically activated.

In advanced mode, you can:

• change the name of the axes

• change the color of the axes by clicking on color button

• change the Length of the line and Add arrows at the extremities