Measurement 3D – Plumb-bob

Measurement 3D – Plumb-bob

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. Therefore, it is easier to 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.

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.


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. It shows it by default only once. It you want to see it again, you can reactivate it from the preferences menu.

Different types of frame for different use cases

A reference height to get accurate measurements

To estimate distances, the application relies on the camera height. The application can not guess this height and you must manually enter it. 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 you adjust only one distance at a time. The application deduce the 2 others from the first one.

The app shows the distance estimations 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 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: your phone system normally reports this information. 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

Download “Measurement 3D – Plumb-bob” now and start measuring the world around you!

3D Measurement App - Plumb-bob
3D Measurement App - Plumb-bob
Developer: Assysto
Price: Free
3D Measurement App - Plumb-bob+
3D Measurement App - Plumb-bob+
Developer: Assysto
Price: $1.49

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