AutoCAD Training Tip - Use the UCS Command to Draw on Any Plane

In this quick AutoCAD?lesson, you learn how to use the UCS command to draw on any flat plane in 3D space. You will find mastery of the UCS command a requirement for any 3D modeling you do in AutoCAD.? Although the user interface is a bit confusing, with a little training you'll find the using UCS becomes intuitive.

As you may or may not remember from your highschool geometry class, a plane is defined by three points in space.? User Coordinate Systems created using the UCS?command are also defined by three points.? The points can defined by 3 X,Y,Z coordinates, or they can be defined by an origin and rotation along the X, Y and Z axis.

To experiment with the UCS command

1. Start by drawing a square in model space.
2. Select the square, then right-click and choose Properties. Set the Thickness of the square to 10. this will make the lines of the square extrude into the third dimension.? If you prefer, you can use the EXTRUDE?command to make the square into a solid box.
3. From the View menu, select the options required to display a 3D view of the model.

Now, to draw something on the side of the box.

1. From the Tools menu, choose New UCS, then 3 Point.
2. Select the lower left corner of the box. You are defining the 0,0,0 for the coordinate system.
3. Using OSNAP's select the lower right corner of the box. You are defining a point on the X-axis of the new coordinate system.
4. Using OSNAPs, select the upper left corner of the box. This is a point on the Y axis of the new coordinate system. Note the change in the UCS icon located in the lower left corner of the screen. This is showing you the orientation of the X, Y and Z axes.

To get back to the normal drawing plane, type UCS?at the command prompt, then type W.? This will return you to the default World coordinate system.? Take time to experiment with the the UCS?command.? When you can draw geometry on any plane in 3D Space, you are well on your way to being able to create 3D surface and solid models in AutoCAD.

Nancy Fulton has been teaching folks to use AutoCAD for twenty years. You can find her tutorials at http://www.complete-support.com and http://learn-autocad.blogspot.com/.