The Measurement Tool
Measure distances in an orthographic level viewport by dragging with the middle mouse button.
You can access the Measurement Tool by holding down and dragging the middle mouse button within a level viewport that’s set to an orthographic view, such as Top, Front, or Left. The editor draws a line from where you started to where your cursor is, with the length printed at its midpoint.
In a perspective view, dragging with the middle mouse button moves the camera instead, so make sure you’ve switched to an orthographic view first. Holding Ctrl, Alt, or Shift while you drag also stops the measurement from starting.
Does grid snapping affect the measurement?
Yes. When grid snapping is on in the viewport toolbar, both ends of the line snap to the current location grid size. Turn grid snapping off when you need to measure between points that don’t sit on the grid.
How can I change the displayed unit?
Set the Measuring Tool Units option under Editor Preferences > Level Editor > Viewports > Look and Feel. You can pick Centimeters, Meters, or Kilometers, and the default is Centimeters. Since one Unreal unit is one centimeter, the default readout matches your world units.
Centimeter readouts are whole numbers, while meters show up to one decimal place and kilometers up to two, depending on how far you’re zoomed in.
Frequently asked questions
Why isn’t anything drawn when I drag?
The tool only draws once the line is at least 1 unit long, so a very short drag shows nothing.
Can I change the color of the line?
Yes. The Viewport Tool Overlay Color option under Editor Preferences > General > Appearance > User Interface sets the color of the line and label. The default is white.
Links
Check out the following resources to learn more about the subject.
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