Handling Coordinates with Named UCS in AutoCAD

In some situations, users may run into issues when the coordinates for their facility are too far from the origin for AutoCAD to correctly process the model.

Background Information

Please see these articles for more details about the types of issues that may arise:




Here are some links showing how Microstation handles the issue:



There are four scenarios used with Plant 3D. The scenario not often covered is how to use a named ucs.

Listing Real-World Coords

Typically we have some sort of background referenced in our piping model. In this workflow, a user in the fields needs some quick information about the coordinates for a piece of equipment. We need to set up our models so that we can provide the coordinates as needed in the future.

The drawing below shows a site layout with our coordinates called out.

First we move our benchmark to the origin.

Then you can trace lines along the outside of the building to align our axis, change the x-axis of the ucs by dragging along the lines we just drew.

Type in UCS at the command line, and then you can enter #-3309′,-5604′ (moving the ucs in the negative direction so that our coordinates are positive). Hit enter again to accept the default x-axis.

To save our UCS, enter UCS again, and then (NA for named), S for Save, and enter a ucs name (like Plant UCS).

On the modeling tab, you can see the current/available ucs.

They are also available in the Navigation Cube.

At any point now, you can use the ID command to identify plant coordinates in your model.

Displaying Coordinates on Plans and Sections

The final piece of the puzzle is showing the coordinates on plans and sections. To do this, you first have to setup your ucs in your ortho template. Then you can use ordinate dimensions to callout locations as needed.

Here are two ordinate dimensions to the tank center using the model coordinates

Set the Plant UCS in the viewport, and then get the plant coordinates.