Autodesk Developer Network 2011
Autodesk
Point Cloud Client API 
§Autodesk.Revit.DB.PointClouds namespace
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§Major classes
§PointCloudInstance
§PointCloudType – represent the points obtained from a single file or engine identifier
§CloudPoint – an individual point. (x, y, z) in cloud coordinate, and a color
§PointCollection
§PointCloudFilter – volume filter. Use PointCloudFilterFactory.CreateMultiPlanerFilter()
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§Two ways to access
§IEnumerable – traditional “for each” access IPointCloudEngine interface
§GetPointBufferPointer()
§Direct access to the unmanaged world
§C# or C++/CLI only 
§Unsafe
§Performance gain
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New classes, interfaces, and structure for Revit Point Cloud are added in PointClouds namespace.

The major classes of the client API are listed below –
PointCloudInstance – deals with the instance of point cloud in a location
PointCloudType – represents the points obtained from a single file or engine
CloudPoint – refers to an individual point cloud point (representing a coordinate and color).
PointCollection- as the name suggests, refers to a collection of points obtained from instance and filter
PointCloudFilter – refers to the volumetric filter used to filter points as per specific region of interest

Two ways to access the points as client –
1.Using the traditional IEnumerable interface, we can iterate through the resulting points from the point collection
2.In unsafe interface usable only from C# and C++, we can get a pointer to the point storage collection and access each one in memory using the GetPointBufferPointer(). This might even have performance gain while traversing through large buffers of points.