I currently have a code where I can import a point cloud, select a specific area via pcl::visualization::AreaPickingEvent and crop that area out. So far I am selecting the area via VTK rubberband feature (triggered by x or X). However, instead of having a rectangular shape to select the points, I would like to have a cube that would select only the points inside the cube. I am currently using QT, C++, VTK and PCL. Is there any QT function that would do that?

In Summary:

What I have now: trigger x, drag a rectangle, crop the area (with the entire depth)

What I want: drag a cube shape, select the area inside the cube, crop that area out