User Coordinate Systems

When you create entities in a drawing, they are located in relation to the drawing's underlying Cartesian coordinate system. The ELEVATION system variable specifies the distance from the xy-plane of the current coordinate system. If ELEVATION = 0 (zero), entities are created in the xy-plane of the current coordinate system.

Every drawing has a fixed coordinate system called the World Coordinate System (WCS).

You can also define arbitrary coordinate systems located anywhere in three-dimensional space. These are called user coordinate systems (UCS) and can be located anywhere in the WCS and oriented in any direction. You can create as many UCS as you want, saving or redefining them to help you construct three-dimensional entities. By defining a UCS within the WCS, you can simplify the creation of most three-dimensional entities into combinations of two-dimensional entities.

When you create a new drawing the WCS is the current coordinate system by default, which is indicated by the letter W in the UCS icon. When you display a drawing in plan view, you see the coordinate system icon from the top, with the z-axis directed straight toward you. When you display a three-dimensional drawing in a view other than plan view, the coordinate system icon changes to reflect your new viewpoint.

NOTE	You cannot delete or modify the WCS.

To help you keep your bearings in the current coordinate system, BricsCAD displays a coordinate system icon (UCS icon). The visible portions of the axes are the positive directions.


WCS Top View	UCS Top View	WCS Isometric View	UCS Isometric View

Three colors represent the three axes, making it easier for you to recognize the orientation in three-dimensional space:

x-axis: red
y-axis: green
z-axis: blue

The Plan View command restores the Plan view or Top view of the current UCS or WCS.

The UCSICON settings variable controls the display and location of the UCS icon:

Show icon:

Controls whether the icon shows or not.

at origin:

Controls the location of the UCS icon: if on, the icon indicates the origin point of the current coordinate system (UCS or WCS). However, if the origin is not within the viewport borders, the UCS icon moves to the corner of the viewport, as defined by the UCSICONPOS (UCS Icon Position) settings variable.
When the at origin option is not checked, the icon always displays in the corner of the viewport defined by UCSICONPOS.

Dynamic UCS

With the Dynamic UCS feature enabled, the coordinate system is aligned automatically with a face of a solid when drawing entities.

This feature is controlled by the UCSDETECT system variable.

To toggle the dynamic UCS

Do one of the following:

Press the F6 function key.
Click the DUCS field in the status bar.

Using the Dynamic UCS

With the Dynamic UCS feature active, launch a Draw command.
Move the cursor over the face of a 3D solid.

The face highlights.
If ON, the grid is aligned with the selected face.
If the UCSICON system variable = 3 (On at Origin), the UCS icon displays in the selected face.

Pick a point to start drawing.
When the drawing command concludes, the current UCS or WCS is restored.

To define a User Coordinate System

Choose Drawing Explorer > Coordinate Systems in the Tools menu.
The Drawing Explorer - Coordinate Systems dialog opens.
Click the New tool button () on the Drawing Explorer dialog.
The BricsCAD Explorer dialog closes.
The command bar reads: Current/Entity/Origin/View/X/Y/Z/ZAxis<3point>:
A prompt menu displays:

Press Enter to define the UCS using points.
The command bar reads: New origin <current origin>:
Specify the origin point of the UCS.
The command bar reads: Point of positive X axis <current point>:
Specify a point to define the positive X-axis.
The command window reads: Point in X-Y plane with positive Y value <current point>:
Specify a point to define the positive Y-axis.
The UCS is defined.
The BricsCAD Explorer dialog reopens.
Click in the UCS Name field of the newly defined UCS to replace the <NewUCS> default name.
Close the BricsCAD Explorer dialog.

Command Options

See the EXPUCS and UCS commands.

To restore the WCS

Type UCS in the command bar, then press Enter.
The command bar reads: ?/3point/Delete/Entity/Origin/Previous/Restore/Save/View/X/Y/Z/Zaxis/<World>:
A prompt menu displays.
Do one of the following:
Press Enter to accept the default option.
Choose World in the prompt menu.
Type W in the command bar and press Enter.

To restore a UCS

Choose Drawing Explorer > Coordinate Systems in the Tools menu.
The Drawing Explorer - Coordinate Systems dialog opens.

Click the blank tile in front of the UCS name to make it current.
Close the BricsCAD Explorer dialog.

NOTE	If no UCS is marked, the WCS is the current coordinate system.

To set a relative UCS

Do one of the following:
Click the UCS... tool button () on the Settings toolbar.
Choose UCS... in the Settings menu.

The User Coordinate System dialog opens.

Choose one of the following:

Set the selected UCS relative to the Current UCS.
Set the selected UCS relative to the World coordinate system (WCS).
(option) Enable the Change view to plan view of the selected UCS option.
Click one of the Planar UCS's buttons.
The User Coordinate System dialog closes.

NOTES

If the UCSORTHO system variable is ON an orthographic UCS is restored automatically when an orthographic view is restored by the -VIEW command or by one of the tools on the Look From toolbar.
The UCSVP (UCS viewports) system variable controls whether the UCS in a viewport is fixed (UCSVP = ON) or changes to match the UCS in the current viewport (UCSVP = Off). As a result, in a multiple viewport drawing, the UCS of all viewports that have UCSVP = Off matches the orthographic UCS of the current viewport if UCSORTHO = On.

Command Options

See the SETUCS command.