How to Modify the UCS (User Coordinate System) in AutoCAD

by George Mylne // Last edited October 2, 2022
AutoCAD modifying UCS Step 11 UCS and delete objects 220417

Being able to modify the user coordinate system (UCS) in AutoCAD is the first step to being able to draw more complex 3d objects. This is done by using the UCS command.

Watch the video below or on YouTube to see how this command can help you with your 3d drawing or follow the instructions below that.

AutoCAD modifying UCS Step 7 orbit to view drawing 220417

How to Modify the UCS (User Coordinate System) in AutoCAD

Total Time: 1 minute

  1. Check current UCS/WCS state

    AutoCAD modifying UCS Step 1 220417

    Under the ViewCube check that it is showing WCS, and if it isn’t then select WCS from the dropdown list.

    If you can’t see your ViewCube, read my blog here about recovering the ViewCube.

  2. Draw circle in XY plane

    AutoCAD modifying UCS Step 2 draw a circle 220417

    Using the circle command CIRCLE (shortcut = C) select anywhere and anysize to draw a circle.

  3. Orbit model space

    AutoCAD modifying UCS Step 3 orbit view 220417

    Holding Ctrl and pressing the middle button on your mouse rotate the view around so you are looking at the front of the ViewCube.

  4. Select view from ViewCube

    AutoCAD modifying UCS Step 4 Use cube to change view 220417

    When you can see the front of the ViewCube click it and the model space will snap to that view.

  5. Draw circle in XZ plane

    AutoCAD modifying UCS Step 5 UCS command 220417

    To be able to easily draw an intersecting circle in the XZ plane, type in UCS into the command bar, and select or type in VIEW.

    This will change the UCS to match your current view.

  6. Draw second circle

    AutoCAD modifying UCS Step 6 draw second circle 220417

    You can now start the CIRCLE command and snap to the centre of the existing circle, and draw it at the same radius.

  7. Inspect results

    AutoCAD modifying UCS Step 7 orbit to view drawing 220417

    You can now view your results by orbiting the model space by holding Ctrl + middle mouse button and rotating around the model space.

  8. Reset ViewCube to WCS

    AutoCAD modifying UCS Step 8 reset view to WCS 220417

    Once you have finished working in your custom UCS, you can reset the model space/ViewCube one of two ways:
    (1) Type in UCS into the command bar, then type in WORLD to reset to WCS (world coordinate system)
    (2) Underneath the ViewCube select the dropdown list and select WCS from the list.

  9. Example 2 – Non square UCS

    AutoCAD modifying UCS Step 9 Non square ucs 220417

    To create a UCS that isn’t square to the ViewCube (i.e. you can’t just press different faces of the view cube), what I do is draw my own axis by copying the feature I want my UCS to be aligned with and rotating it 90 degrees.

  10. Draw axis

    AutoCAD modifying UCS Step 10 draw axis you want 220417

    Drawing the axis is a pretty manual step. You can do this using the line and copy and rotate commands.

  11. Create custom UCS

    AutoCAD modifying UCS Step 11 UCS and delete objects 220417

    Type in UCS into the command line and then just follow the prompts:
    (1) Select an origin point
    (2) Select the direction of the X-axis
    (3) Select the direction of the Y-axis
    (4) Select the direction of the Z-axis

    You can see the resulting axis as it appears in the above image at the end of the line.

    If this step is confusing watch my video starting from here.

Final Thoughts

I hope this video was useful to you.

Being able to modify the UCS is a basic step to being able to draw more complex 3d shapes and objects.

FAQs

How can I get my UCS back to normal?

You can either:
(1) Type in UCS into the command bar, then type in WORLD to reset to WCS (world coordinate system)
(2) Underneath the ViewCube select the dropdown list and select WCS from the list.

How do I reset my UCS?

You can either:
(1) Type in UCS into the command bar, then type in WORLD to reset to WCS (world coordinate system)
(2) Underneath the ViewCube select the dropdown list and select WCS from the list.

How do I rotate the model space view to match the viewcube?

You can press the faces on the ViewCube to modify and change your view of the model space.

About the author George Mylne

George has been a surveyor for over 13 years, working across a wide range of projects and industries. In this blog, he shares his experiences and information gathered from his time on mining, civil and surveying projects.

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