Point cloud cuboid annotation

How to draw cuboid annotations over Lidar data using the Mindkosh annotation platform

There are 2 ways to label cuboids in 3D pointclouds - Magic Select and One-click annotation. We describe both of them below.

One Click annotation

Using this method, you can label an object with just one click! To use it:

  1. Choose a label for the object from the left sidebar.

  2. Select the Draw cuboid tool from the left sidebar.

  3. As you move your mouse over the pointcloud, you should now see a small yello circle around the points as you hover over them.

  4. Find a point that belongs to the object, make sure you don't accidentally select a point behind the object.

  5. Hold the ctrl key on the keyboard and click on the point.

  6. The cuboid should now be drawn.

Magic Select

One click annotation works by using a technique called clustering. In some cases, where points of an object are far apart, this may not work. In such cases, you can use the Magic select tool to draw cuboids. Here is how it works:

  1. Choose a label for the object from the left sidebar.

  2. Select the Draw cuboid tool from the left sidebar.

  3. Hold you right mouse button and draw a rough outline slightly inside the object.

  4. The cuboid should now be drawn

Editing a cuboid

Once drawn you have a few options to edit the cuboid

Using top/side/front views

When you select an object, it's top, side and front views are shown at the bottom. You can click and drag the corners of these planes to change the dimensions of the cuboid. This is the easiest way to update a drawn cuboid

Using the resize panel

When an object is selected, a resize panel appears over the pointcloud. You can use this to resize, rotate as well as move the cuboid.

Step size Sometimes you may want to make really large or really precise changes. Using the text box on the right side of each section, you can change the step size for every button press. Setting a lower value will help you make precise changes. Making the step size large will allow you to make large changes quickly.

Cuboid size section The first two rows in the panel are for updating the length, width and height of a cuboid. There are 6 sets of +/- buttons for the 6 faces if the cuboid. For e.g. The set of buttons in the first column and second row, refers to the bottom face of the cuboid.

Rotation section The third row allows you to rotate the cuboid in the X, Y and Z axes, in anti-clockwise( + buttons ) and clockwise( - buttons ) directions. At any point, clicking on the Reset button will reset all rotations and bring the cuboid back to 0° in all axes. The default step size is 2° - which means that for each press of the buttons, the cuboid will rotate by 2°. You can change that by entering a new value in the step size text box.

Translation section This section allows you to move the cuboid in X, Y and Z axes.

Using Keyboard shortcuts

All of the operations listed above can also be performed using convenient keyboard shortcuts. You view a list of the available shortcuts by clicking on the Shorcuts icon at the top, as shown in the image below. You can also view a list of all the shortcuts here.

Marking front facing face

To mark the front facing face(side) of a cuboid, use the Forward face section in the resize panel. Once marked, the front face will be highlighted.

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