LibreCAD Convert Drawing Units

LibreCAD Drawing Units "Blueprint Ruler" by Wokandapix is licensed under Pixabay License.

Fixing the unit type of LibreCAD drawings is simple, not fixing it will cause lots of problems down the road. Depending on whether you want the drawing to remain the same physical size or to just correct setting the wrong unit type, there are two ways to go about it.

Fixing Incorrect Unit Type

If you started a drawing without realizing it was drawn while set to the wrong unit, changing to a different unit is easy. This will change the “label” of units but not alter the size of the drawing unless imported into other documents.

  1. Open Options > Current Drawing Preferences
  2. Switch to the “Units” tab.
  3. Set the “Main drawing unit” to the correct unit.

This change will change the unit type but not the dimensions and will not scale your drawing. If you were previously working with centimeters and switched to inches, your 100cm square will become a 100in square.

The lines, shapes, and arcs inside a DXF file are unitless. Inside the header of the file stores the unit type of the document. The above steps simply change the setting of unit type without making any altercations to the actual drawing.

Change Correct Unit Type

If you have a drawing that was made with the correct unit in mind initially but later have to change it to a different unit, you’ll want the drawing to scale in proportion to the new unit to keep the drawing the same physical size.

  1. Create a new document.
  2. Open the menu Options > Current Drawing Preferences
  3. Switch to the “Units” tab.
  4. Set the “Main drawing unit” to the new unit you want.
  5. Open the menu File > Import block. Import the drawing you want to use a new unit for.
  6. Highlight or select the block inside the drawing.
  7. Go to Tools > Modify > Explode.
  8. Delete the block inside the “Block List” since it is no longer needed.

When you take measurements of the drawing now, it should be in the new unit and physically resemble the same size as the previous unit. Your 100in square will now be a 254cm square if switching from inches to centimeters.

Exploding the block may not be necessary depending on what you plan on doing with the drawing. If you simply need to print the plans with a different unit, exploding is generally not required. Importing blocks that use a different unit than your main drawing also works fine and the block doesn’t need to be exploded.

You will need to explode the block if you plan on making altercations to the drawing under the new unit.