Support
How to change the density of a point cloud?
Summary
In Tcp PointCloud Editor you can reduce the density of a point cloud using the density selection, which marks the points lying within a given radius of another already processed point so that you can then hide or delete them. It is the usual tool both for lightening very heavy clouds that cause performance problems and for extracting a less dense grid within a delimited area. Increasing the density (densifying by interpolating new points) is not a function available in the application.
Applies to
Tcp PointCloud Editor. The documented cases do not state version numbers.
Point selection and editing functions (density selection, filter selection, delete, consolidate).
Symptoms
You need to generate additional points to densify a cloud within a given outline and cannot find the option.
A large cloud takes a long time to load during some commands and does not seem to save correctly.
You need to extract a less dense mesh or grid of points from a dense cloud, restricted to a boundary or area of interest.
Cause
Tcp PointCloud Editor has no function that interpolates new points in order to increase the density of a cloud.
Poor performance and saving problems in very large clouds are usually due to a density that is excessive for the size of the set and the capacity of the computer.
Solution
Case: increasing the density (densifying) of a cloud
Tcp PointCloud Editor does not allow point clouds to be generated with a specific density, nor densifying by interpolating new points within an outline. This function was recorded as a suggestion for possible future implementation. If your aim is the opposite —reducing the density—, follow any of the cases below.
Case: reducing the density of the whole cloud (density selection)
Run the density selection command, in the Editing menu: depending on the version, the group appears as Geometric Selection or as Select, and within it the By Density option.
Enter the neighbourhood radius (search radius). The command processes the points and selects those that are at a distance smaller than the radius from a previously processed point.
Once the selection has finished, hide or delete the selected points. The resulting cloud will have the given radius as its minimum spacing between points.
Case: improving the performance of a very large cloud
When a very heavy cloud takes a long time to load in some commands and does not seem to save correctly, reducing its density usually solves the problem:
Run the density selection, in the Editing menu, as described in the previous case.
In the search radius, enter a value that is reasonable for the job; between 2 and 5 centimetres is usually a good approximation.
Accept to apply the filter. This may take a while if the cloud is very dense. When it finishes, the points that do not meet the distance criterion will be selected.
Delete those points with Editing > Edit > Delete.
Consolidate the cloud to confirm the deletion and reduce the size on disk: in the project panel (left-hand side of the screen), right-click on the point cloud (if there are several, select them all and right-click on any of them) and choose the Consolidate… option, which is the first in the menu.
Case: extracting a less dense grid within a delimited area
Make a point selection by rectangle or polygon to select the points of the area of interest (boundary or edge).
Use the filter selection command to keep only those points.
Then apply the density selection, which marks the «surplus» points (those lying within a distance smaller than the one defined from other points that remain unselected).
Hide or delete the selected points. Another possibility is to assign them to a category —for example, «Noise»— and then hide that category: its points stop being displayed but remain in the cloud in case you need them later.
The result will be a cloud limited to the area of interest and with a spacing between points equal to or greater than the one set.
If the problem persists
If reducing the density does not improve performance, or the problem appears in another process, describe in detail the type of problem, the size of the cloud and the step at which it occurs; you can record a video or request a remote connection so that support can identify it.
If you need to increase the density of a cloud for a specific workflow, tell Aplitop technical support: densification is recorded as a suggestion and it is useful to know the use case.
Category: Point cloud display and editing · Level: Intermediate