Point cloud refinement

In the accessories menu or through the toolbar there are three tools that control the refinement of the point cloud displayed. These are:

Define Volume

Define volume enables the user to define a rectangular cuboid by making 2D selections within the 3D window. This is then used to request a volume from the point cloud in a higher resolution. On selecting the button shown below, the view is changed to a bird’s eye view of the site, enabling the user to define a 2D box by holding the left button and dragging the mouse.

When the mouse button is released, the view switches to a side view of the site, enabling the user to drag a box to define the volume height. The direction of this view can be toggled using the left or right arrow keys. The vertical guidelines provide an aid to the user showing the area that remains to be defined. After the volume selection, the function automatically toggles the low-resolution seed points off so only the refined points are displayed.

The example below shows the Define Volume tool in action.

Define Volume by Selected Element

This tool has the same result as the Define Volume tool.

However, rather than creating a volume by using a mouse, a volume can be created from the boundary of particular elements. After the particular elements, for example, pipe work, steel work, cables, and so on, have been selected using the mouse, this tool can be run to get the tightest bounding box around the elements. This box is then expanded by the additional volume padding value specified in metres within the options dialogue.

The example below shows the volume selection using this method, using a point density value of Dense and a volume padding of 0.0 metres, giving us the tightest volume possible about the selected elements.

Zoom Extents

This function enables you to immediately navigate and zoom to the full extents of the point cloud data. This function sets the new rotation point to be the center of the point cloud, and zooms the display accordingly so the point cloud fills the 3D window. If a volume is selected and seed points are turned off, selecting this function will zoom to the extents of the selected volume.

Reset Volume

This enables you to cancel any point cloud volume that has been defined, whether it be for using the Lasso Line tool to the Define Volume by Selected Element tool. As well as cancelling the volume this function also toggles the seed points on.

In the options dialogue, launched from the Command Control tool bar, there is a field which specifies the point cloud resolution as a result of a volume selection:

The options presented are:

• Sparse

• Normal

• Dense

• Super Dense

Select the appropriate density and then select Apply. This updates the current volume to the new density level.

If the Super Dense option is used with any of the volume refinement selection tools, all the points captured within that volume by the laser scanner are displayed.

Volume Padding is effective when the Define volume by selected element tool is used, and the point density tools are also effective here.

When you are satisfied with the changes, select OK to close the dialogue. To close without applying the changes, select the red cross to the upper right of the dialogue.

To open the S3D CAD link manual, select the icon shown below: