PCD - Point Cloud Data
What is a PCD?
The data for a Point Cloud can be provided by Blueprint, a Cube-Dataset, a PLY-File, a Material or a Static Mesh. If you open a PCD Data Asset, within the “PointCloudKit Content / Examples / PointCloudData” folder, you can see the different parameter collections for each creation methode. The first bool in a collection is called “Generate by …” and will activate that methode (only one can be active at once).
Point Cloud by Blueprint
This option will inform the Actor that it will be initialized by Blueprint. Any PointCloudActor has a PointCloudSystemComponent. Most of the Blueprint functions on the component itself will be also present on the Actor (for convenience). But to initialize the data, you need to access the arrays “PointLocations” and “PointColors” on the PointCloudSystemComponent directly. Fill these arrays and call the Blueprint function “UpdateData” on the Actor. For example take a look at the InitPointCloudData function in the BlueprintActor called PointCloudActor_Wave_BP (within the Examples/Blueprints folder). Note that for initializing a Point Cloud this way you actually don’t even need to have any PCD present but it is recommended, because this is the only way you can also override the Particle System template (more details look at Particle System Emitters). Use Blueprints only for initializing a Point Cloud and not for animation, because it is very slow (CPU bound), use a Material (GPU bound) within a PCA Data Asset instead.
Point Cloud by Cube
This will create a cube, plane or row grid distribution of Points. Useful as a starting point or for testing.
Point Cloud by File
Currently the PLY ASCII file format is supported: de.wikipedia.org/wiki/Polygon_File_Format
Because there are no polygons nor edges in a Point Cloud, only the Vertex and Color data will be loaded. With the remapping feature you can load any kind of vertex property to a specific color channel. For example a LiDAR scan may have an “intensity” property, which can be remapped to the alpha or any other channel. Colors can be in uchar (0-255) format or in float32 (1.0 - 0.0) as Linear Color.
Point Cloud by Material
Internally all the position data will end up in a 2D floating point Render Target. The Unreal Engine™ provides a function called UKismetRenderingLibrary::DrawMaterialToRenderTarget which will render a Material as pure data calculations into a Render Target, without the need of a camera or viewport setup. The PointCloudKit framework provides an interface to script your own Materials to initialize (PCD) and animate (PCA) a Point Cloud. For more details on the Materials look at Materials for Location and Color.
Point Cloud by Mesh
The vertices in a Static Mesh, with their location and vertex color, will be used to create a Point Cloud.
These properties are independent of the import method. It will override the Particle System template or Material (for rendering the Particles) referenced by the Point Cloud. Otherwise the default Particle System template will be used, which can cause issues with multiple Point Clouds in a scene (more details look at Particle System Emitters).