Plumb-bob application for Android

A handy tool, always in your pocket!

The "Measurement 3D - Plumb-bob" app is a handy application which makes use of the phone internal sensor and camera to display a virtual plumb-bob. With this application you can check that lines are vertical or horizontal, verify proportions, or check that an object is properly centered.
This tool comes with a snapshot feature. In this mode, it is no longer required to hold the device in the air. You can precisely adjust the position of the plumb-bob in the picture and you can also rotate the frame to align it with a wall that is not directly facing you.
When you save this snapshot, you do not simply save an image. You record a complete 3D scene, and you have the ability to later measure any part of it! This is useful when you go shopping and wonder if a piece of furniture can fit in your living room. Or if you plan to move and wonder if your wardrobe will fit in the truck.

How to get it?

"Plumb-bob" is available on Google Play™.

QR Code

A paid version "Plumb-bob+" contains extra features:

  • no limit to the number of 3D scenes saved in library,
  • increase of the number of rows and columns of the grid up to 20,
  • plumb bob in 3D shape (box or cylinder),
  • estimations of surfaces and volumes,
  • higher sensor refresh rate which allows a smoother animation. The rate can be adjusted with the preference menu,
  • possibility to customize colors and font size.

QR Code


Check this video to learn how to use this app:

The app contains an inline tutorial that will guide you the first time you use it. This tutorial is by default only shown once. It you want to see it again, you can reactivate it from the preferences menu.

Different types of frame for different use cases

The vertical rectangular frame can be used to check wall tile alignment. The number of rows and columns can be adjusted using the preferences menu. With the paid version, these numbers can be increased up to 20.
Checking wall tile alignment

If you activate the 3D box virtual frame, you can estimate the volume of a piece of furniture (paid version only).
Measuring volume

You can also measure an angle to the vertical:
Angle measurement

A reference height to get accurate measurements

Distance estimations are shown in a black rectangle that you can move around with your finger. Here is the explanation of the meaning of each value:

  • H: the camera height (see the calibration section to learn how to adjust it)
  • D: the estimated distance from your feet to the plumb-bob bottom (that is supposed to touch the ground)
  • w: the estimated frame width
  • h: the estimated frame height
  • d: the estimated frame depth when in 3D
  • z/x: the height/width ratio
  • a: the estimated angle value
  • S: the estimated 2D frame surface
  • V: the estimated 3D frame volume

The screenshot below shows the estimated distance to a door and its size (width and height):
Size measurement

To estimate distances, the application relies on the camera height. This height can not be guessed by the application and must be manually adjusted. There are buttons on the right hand side for that. There are 2 ways to adjust the camera height:

  • you can set the height directly (measure the distance of the camera from the ground and try to keep it at the same height during all your measurements),
  • or, if you know precisely the measure of an horizontal or vertical segment, make sure the virtual frame is aligned to it, and fill the corresponding field (the camera height will be automatically computed from this measurement).

Note that only one distance can be adjusted at a time, the 2 others are deduced by the application from the first one.


The calibration page (which opens with the calibration button of the main page) allows to adjust 2 parameters that are necessary to perform correct measurements: the camera angles of view, and the internal sensor calibration.

Camera angles of view: this information is normally reported by your phone. However, some manufacturers do not provide a valid value. In that case you must measure those angles manually and fill the corresponding fields. If the invalid values are not corrected, the plumb-bob line will still be displayed vertically, but the frame sides will not.

Internal sensor calibration: as the device internal sensor is not always accurate, this tool comes with a calibration feature:
Look at the Support page, where there is a video that explains how to use this feature.


We hope you will like this app. Please post a nice comment on Google Play if this app has been useful to you.
If you have an idea to improve this app, do not hesitate to email us.

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