Resampling a Cloud
Point Cloud has two methods of cloud reduction. There is a
fast, naive method, and a slower, more intelligent method.
To resample a Cloud, right-mouse click the cloud in the Current
Project tree and select Resample. This will
open the Resample Cloud dialog.
Step method is much faster at the cost of being
less intelligent. It will simply reduce the cloud to 1 / Step its
current size by only keeping one out of every nth vertices.
For example, a step size of four, Resample will traverse the cloud
and only keep every fourth vertex, deleting three for each one it
keeps.
Oc-Tree tree method is a more intelligent process,
but it can have significantly longer run times than the Step
Method. The Oc-Tree creates a bounding box based on the "Oc-Tree
Dimensions" settings. This bounding box is then subdivided into
blocks (nodes) based on the "Oc-Tree Resolution" settings. The
points in each block (node) in the Oc-Tree is then filtered
according to the "Oc-Tree Nodes" settings.
- Oc-Tree Dimensions: The extents
("Minimum"<->"Maximum") in the x,y, and z dimension of the
Oc-Tree's bounding box.
- Oc-Tree Resolution: Defines the number of blocks
(nodes) included in the Oc-Tree such that resolution*delta=extents
(in x,y, or z dimension).
-
- Delta: Extents of one of the Oc-Tree's blocks
(nodes) in the x,y, or z dimension.
- Resolution: Number of blocks (nodes) in the x, y,
or z dimension.
- Oc-Tree Nodes: Specifies how the Oc-Tree filters
points. If a block (node) in the Oc-Tree contains fewer than
"Minimum" number points, the contents of that block (node) will be
deleted. If a block (node) has more than "Maximum" number points,
random points within that block (node) will be removed until it has
"Maximum" number points inside it.
Click the Green Tick to resample the Cloud. The new Cloud
will be displayed in the Clouds sub-menu of the Current
Project tree.
See also: Clean Cloud