Point Cloud Partitioner Step

Overview

The Point Cloud Partitioner step is an interactive plugin for the MAP-Client.

This tool takes a Zinc compatible point-cloud EX file as an input and provides a GUI that gives the user a number of tools to help separate these points into groups. The Point Cloud Partitioner step outputs another Zinc compatible EX file with the points separated into groups defined by the user.

Specification

Information on this plugin’s specifications is available here.

Configuration

Information on this plugin’s configuration is available here.

Workflow Setup

Information on setting up a workflow with this plugin can be found here.

Instructions

When the tool loads for the first time you should see something like the image displayed in Fig. 67.

../../_images/point-cloud-partitioner-initial.png

Fig. 67 Point Cloud Partitioner user interface just after loading.

The coordinate fields used for the point-cloud and mesh data are determined automatically but can be changed using the combo-boxes in the Coordinates section if required.

If the points appear too small or if they aren’t initially visible, try increasing the Point Size value under the Visibility section.

Selection

The scene viewer currently has two modes: View and Selection - indicated by the text in the bottom left of the view window. View mode is activated by default and allows the user to change the position of the scene items with the mouse. Selection mode can be activated by holding the S key on the keyboard. The user can select a single point at a time or drag a selection box over all the points they wish to select.

There are multiple different methods for selecting points in the scene - indicated by the Selection Mode combo box in the Selection section. These modes include Exclusive, Additive and Intersection. Exclusive mode is selected by default and will clear all previously selected points each time the user makes a new selection. Additive mode will add all selected points to the current selection each time the user selects a new set of points. Intersection mode will select all points in the current selection box only if they were already selected.

See Advanced Selection for information on: selecting points associated with a specific mesh surface, and separating point groups into subsets.

Grouping Points

To create a new point group click the Create Group button in the Group Points section. This will add a new label to the Group Points section of the GUI, as well as a sel. button to select all points already assigned to that group. The group name defined in the label can be changed at any time and will be used to identify the group when it is written to the output file. Each point group is automatically assigned a display colour.

It is also possible to manually re-order the group list items in the Group Points section by dragging and dropping the items to the desired locations. Doing so will re-assign the display colour assigned to each of the groups. In the case where a set of points is contained by multiple point groups, the group closest to the top of the list will be displayed “in front” of any other groups containing those points.

Once you have selected the points you wish to group, simply select the desired point group in the Group Points section and click Add Selected Points to Group. Points can be removed from a group again by selecting them and clicking Remove Selected Points from Group. If you wish to remove a point group entirely, select it and click Remove Group.

Note that the buttons to add or remove points from a group will be disabled if there aren’t any points selected. Similarly, the button to delete a point group will only be available if the user has selected a group from the list.

Advanced Selection

This section describes how to select and group all points associated with a given mesh surface, as well as how the user can partition a group of points into smaller subsets.

If the plugin additionally imports a Zinc mesh, it is possible to select all points that are positioned on the surface of that mesh. To achieve this, change the Selection Type to Surfaces and select the mesh surface that you wish to find points on. Picking a mesh with a click or by dragging a selection box over part of it should highlight its entire surface as shown with one of the inner mesh surfaces in Fig. 68.

../../_images/point-cloud-partitioner-surface-selection.png

Fig. 68 Point Cloud Partitioner with a mesh surface selected.

Once the desired mesh surface has been selected, click Select Points on Surface under the Selection section to select all points positioned on the mesh surface. Note that this button will be disabled if there is no mesh currently selected. The Surface-Point Tolerance spin-box determines how close a point has to be to a surface to be selected by this process - by default the tolerance value is set to 0.00001. Fig. 69 illustrates what the scene should look like once this process has completed. Note that the surfaces visibility has been disabled.

../../_images/point-cloud-partitioner-surface-points.png

Fig. 69 Point Cloud Partitioner with mesh surface selected.

Using these steps the user can separate the point-cloud into distinct groups corresponding with the surfaces of the mesh input as in Fig. 70:

../../_images/point-cloud-partitioner-points-grouped.png

Fig. 70 Point Cloud Partitioner with points separated into mesh surface groups.

Finally, the Intersection selection mode can be used on an existing selection if the user wishes to separate a group of points into subsets.

Continuing from the previous step, you can select all points in an existing group by pressing the group’s associated sel. button. Once you have selected the group of points you want to partition, change the Selection Mode to Intersection and drag a selection box over only the subset of points you wish to remain selected:

../../_images/point-cloud-partitioner-selecting.png

Fig. 71 Point Cloud Partitioner with points separated into mesh surface groups.

These points can then be assigned to a new point group as usual, or further partitioned into subsets.

Finishing

Clicking the Continue button will output the point cloud along with its groups to Zinc EX file and will execute any additional workflow steps connected to the Point Cloud Partitioner step. The point groups will be labeled in the output file with the names defined in the Group Points section of the GUI.